diff --git a/libsrc/core/CMakeLists.txt b/libsrc/core/CMakeLists.txt
index 710faa12..9f074709 100644
--- a/libsrc/core/CMakeLists.txt
+++ b/libsrc/core/CMakeLists.txt
@@ -1,6 +1,7 @@
 
 add_library(ngcore SHARED
   archive.cpp
+  bitarray.cpp
   localheap.cpp
   logging.cpp
   flags.cpp
@@ -58,7 +59,7 @@ target_link_libraries(ngcore PUBLIC netgen_mpi PRIVATE ${CMAKE_THREAD_LIBS_INIT}
 install(FILES ngcore.hpp archive.hpp type_traits.hpp version.hpp ngcore_api.hpp logging.hpp
   exception.hpp symboltable.hpp paje_trace.hpp utils.hpp profiler.hpp mpi_wrapper.hpp
   array.hpp taskmanager.hpp concurrentqueue.h localheap.hpp python_ngcore.hpp flags.hpp
-  xbool.hpp signal.hpp
+  xbool.hpp signal.hpp bitarray.hpp
   DESTINATION ${NG_INSTALL_DIR_INCLUDE}/core COMPONENT netgen_devel)
 
 if(ENABLE_CPP_CORE_GUIDELINES_CHECK)
diff --git a/libsrc/core/bitarray.cpp b/libsrc/core/bitarray.cpp
new file mode 100644
index 00000000..daef541e
--- /dev/null
+++ b/libsrc/core/bitarray.cpp
@@ -0,0 +1,143 @@
+/**************************************************************************/
+/* File:   bitarray.cpp                                                   */
+/* Autho: Joachim Schoeberl                                               */
+/* Date:   01. Jun. 95                                                    */
+/**************************************************************************/
+
+/*
+   data type BitArray
+*/
+
+#include "bitarray.hpp"
+
+namespace ngcore
+{
+  BitArray :: BitArray (size_t asize)
+  {
+    size = 0;
+    data = NULL;
+    SetSize (asize);
+  }
+
+  BitArray :: BitArray (size_t asize, LocalHeap & lh)
+  {
+    size = asize;
+    data = new (lh) unsigned char [Addr (size)+1];
+    owns_data = false;
+  }
+
+  BitArray :: BitArray (const BitArray & ba2)
+  {
+    size = 0;
+    data = NULL;
+    (*this) = ba2;
+  }
+
+  void BitArray :: SetSize (size_t asize)
+  {
+    if (size == asize) return;
+    if (owns_data) delete [] data;
+
+    size = asize;
+    data = new unsigned char [Addr (size)+1];
+  }
+
+  BitArray & BitArray :: Set () throw()
+  {
+    if (!size) return *this;
+    for (size_t i = 0; i <= Addr (size); i++)
+      data[i] = UCHAR_MAX;
+    return *this;
+  }
+
+  BitArray & BitArray :: Clear () throw()
+  {
+    if (!size) return *this;
+    for (size_t i = 0; i <= Addr (size); i++)
+      data[i] = 0;
+    return *this;
+  }
+
+  BitArray & BitArray :: Invert ()
+  {
+    if (!size) return *this;
+    for (size_t i = 0; i <= Addr (size); i++)
+      data[i] ^= 255;
+    return *this;
+  }
+
+  BitArray & BitArray :: And (const BitArray & ba2)
+  {
+    if (!size) return *this;
+    for (size_t i = 0; i <= Addr (size); i++)
+      data[i] &= ba2.data[i];
+        return *this;
+  }
+
+
+  BitArray & BitArray :: Or (const BitArray & ba2)
+  {
+    if (!size) return *this;
+    for (size_t i = 0; i <= Addr (size); i++)
+      data[i] |= ba2.data[i];
+    return *this;
+  }
+
+
+  BitArray & BitArray :: operator= (const BitArray & ba2)
+  {
+    SetSize (ba2.Size());
+    if (!size)
+      return *this;
+    for (size_t i = 0; i <= Addr (size); i++)
+      data[i] = ba2.data[i];
+    return *this;
+  }
+
+  std::ostream & operator<<(std::ostream & s, const BitArray & ba)
+  {
+    size_t n = ba.Size();
+    for (size_t i = 0; i < n; i++)
+      {
+	if (i % 50 == 0) s << i << ": ";
+	s << int(ba[i]);
+	if (i % 50 == 49) s << "\n";
+      }
+    s << std::flush;
+    return s;
+  }
+
+  size_t BitArray :: NumSet () const
+  {
+    size_t cnt = 0;
+    for (size_t i = 0; i < Size(); i++)
+      if (Test(i)) cnt++;
+    return cnt;
+  }
+
+  Archive & operator & (Archive & archive, BitArray & ba)
+  {
+    if (archive.Output())
+      {
+        archive << ba.Size();
+        for (size_t i = 0; i < ba.Size(); i++)
+          archive << ba[i];
+      }
+    else
+      {
+        int size;
+        archive & size;
+        ba.SetSize (size);
+        ba.Clear();
+        for (size_t i = 0; i < size; i++)
+          {
+            bool b;
+            archive & b;
+            if (b) ba.SetBit(i);
+          }
+      }
+    return archive;
+  }
+
+
+}
diff --git a/libsrc/core/bitarray.hpp b/libsrc/core/bitarray.hpp
new file mode 100644
index 00000000..9c0823cf
--- /dev/null
+++ b/libsrc/core/bitarray.hpp
@@ -0,0 +1,200 @@
+#ifndef NETGEN_CORE_BITARRAY
+#define NETGEN_CORE_BITARRAY
+
+/**************************************************************************/
+/* File:   bitarray.hpp                                                   */
+/* Author: Joachim Schoeberl                                              */
+/* Date:   01. Jun. 95                                                    */
+/**************************************************************************/
+
+#include <climits>
+#include <cstring>
+#include <ostream>
+
+#include "archive.hpp"
+#include "array.hpp"
+#include "localheap.hpp"
+#include "ngcore_api.hpp"
+#include "utils.hpp"
+
+namespace ngcore
+{
+
+/**
+   A compressed array of bools.
+
+   Provides bit-operations and whole array operations.
+*/
+class BitArray
+{
+protected:
+  /// number of bits
+  size_t size;
+
+  /// the data
+  unsigned char * data;
+  ///
+  bool owns_data = true;
+public:
+  /// empty array
+  BitArray ()
+    : size(0), data(nullptr) { ; }
+  /// array of asize bits
+  NGCORE_API BitArray (size_t asize);
+  /// array of asize bits
+  NGCORE_API BitArray (size_t asize, LocalHeap & lh);
+  ///
+  NGCORE_API BitArray (const BitArray & ba2);
+  BitArray (BitArray && ba2)
+    : size(ba2.size), data(ba2.data), owns_data(ba2.owns_data)
+  {
+    ba2.owns_data = false;
+    ba2.data = nullptr;
+  }
+
+  template <typename T>
+  NETGEN_INLINE BitArray (std::initializer_list<T> list)
+    : BitArray (list.size())
+  {
+    Clear();
+    int cnt = 0;
+    for (auto i = list.begin(); i < list.end(); i++, cnt++)
+      if (*i) SetBit(cnt);
+  }
+
+  /// delete data
+  ~BitArray ()
+  {
+    if (owns_data)
+      delete [] data;
+  }
+
+  /// Set size, loose values
+  NGCORE_API void SetSize (size_t asize);
+
+  /// the size
+  size_t Size () const { return size; }
+
+  /// set all bits
+  NGCORE_API BitArray & Set () throw();
+
+  /// clear all bits
+  NGCORE_API BitArray & Clear () throw();
+
+  /// set bit i
+  [[deprecated("Use either SetBit() or SetBitAtomic()")]]
+  void Set (size_t i) { SetBitAtomic(i); }
+
+  /// set bit i ( not thread safe )
+  void SetBit (size_t i)
+  {
+    NETGEN_CHECK_RANGE(i, 0, size);
+    data[Addr(i)] |= Mask(i);
+  }
+
+  /// set bit i ( thread safe )
+  void SetBitAtomic (size_t i)
+  {
+    NETGEN_CHECK_RANGE(i, 0, size);
+    unsigned char * p = data+Addr(i);
+    unsigned char mask = Mask(i);
+
+    AsAtomic(*p) |= mask;
+  }
+
+  /// clear bit i
+  void Clear (size_t i)
+  {
+    NETGEN_CHECK_RANGE(i, 0, size);
+    data[Addr(i)] &= ~Mask(i);
+  }
+
+  /// check bit i
+  bool Test (size_t i) const
+  {
+    NETGEN_CHECK_RANGE(i, 0, size);
+    return (data[Addr(i)] & Mask(i)) ? true : false;
+  }
+
+  /// set all bits to b
+  BitArray & operator= (bool b)
+  {
+    if (b) Set();
+    else   Clear();
+    return *this;
+  }
+
+  /// check bit i
+  bool operator[] (size_t i) const
+  {
+    NETGEN_CHECK_RANGE(i, 0, size);
+    return Test(i);
+  }
+
+
+  /// invert all bits
+  NGCORE_API BitArray & Invert ();
+
+  /// logical AND with ba2
+  NGCORE_API BitArray & And (const BitArray & ba2);
+
+  /// logical OR with ba2
+  NGCORE_API BitArray & Or (const BitArray & ba2);
+
+  /// copy from ba2
+  NGCORE_API BitArray & operator= (const BitArray & ba2);
+
+  NGCORE_API size_t NumSet () const;
+private:
+  ///
+  unsigned char Mask (size_t i) const
+  { return char(1) << (i % CHAR_BIT); }
+
+  ///
+  size_t Addr (size_t i) const
+  { return (i / CHAR_BIT); }
+
+};
+
+
+  inline BitArray & operator|= (BitArray & me, const BitArray & you)
+  {
+    me.Or(you);
+    return me;
+  }
+
+  inline BitArray & operator&= (BitArray & me, const BitArray & you)
+  {
+    me.And(you);
+    return me;
+  }
+
+  inline BitArray operator| (const BitArray & a, const BitArray & b)
+  {
+    BitArray res = a;
+    res |= b;
+    return res;
+  }
+
+  inline BitArray operator& (const BitArray & a, const BitArray & b)
+  {
+    BitArray res = a;
+    res &= b;
+    return res;
+  }
+
+  inline BitArray operator~ (const BitArray & a)
+  {
+    BitArray res = a;
+    res.Invert();
+    return res;
+  }
+
+
+  NGCORE_API std::ostream & operator<<(std::ostream & s, const BitArray & ba);
+
+  NGCORE_API Archive & operator & (Archive & archive, BitArray & ba);
+
+} // namespace ngcore
+
+#endif // NETGEN_CORE_BITARRAY
diff --git a/libsrc/core/ngcore.hpp b/libsrc/core/ngcore.hpp
index a2cda645..9aa69a6f 100644
--- a/libsrc/core/ngcore.hpp
+++ b/libsrc/core/ngcore.hpp
@@ -3,6 +3,7 @@
 
 #include "archive.hpp"
 #include "array.hpp"
+#include "bitarray.hpp"
 #include "exception.hpp"
 #include "flags.hpp"
 #include "localheap.hpp"
diff --git a/libsrc/core/python_ngcore.hpp b/libsrc/core/python_ngcore.hpp
index 1a071dc2..69a97543 100644
--- a/libsrc/core/python_ngcore.hpp
+++ b/libsrc/core/python_ngcore.hpp
@@ -3,6 +3,7 @@
 
 #include "ngcore_api.hpp" // for operator new
 #include <pybind11/pybind11.h>
+#include <pybind11/operators.h>
 
 #include "array.hpp"
 #include "archive.hpp"
diff --git a/libsrc/core/python_ngcore_export.cpp b/libsrc/core/python_ngcore_export.cpp
index 2f409aa4..e86573ed 100644
--- a/libsrc/core/python_ngcore_export.cpp
+++ b/libsrc/core/python_ngcore_export.cpp
@@ -1,5 +1,6 @@
-
 #include "python_ngcore.hpp"
+#include "bitarray.hpp"
+
 
 using namespace ngcore;
 using namespace std;
@@ -11,6 +12,83 @@ PYBIND11_MODULE(pyngcore, m) // NOLINT
   ExportArray<size_t>(m);
   ExportArray<double>(m);
 
+  py::class_<BitArray, shared_ptr<BitArray>> (m, "BitArray")
+    .def(py::init([] (size_t n) { return make_shared<BitArray>(n); }),py::arg("n"))
+    .def(py::init([] (const BitArray& a) { return make_shared<BitArray>(a); } ), py::arg("ba"))
+    .def(py::init([] (const vector<bool> & a)
+                  {
+                    auto ba = make_shared<BitArray>(a.size());
+                    ba->Clear();
+                    for (size_t i = 0; i < a.size(); i++)
+                      if (a[i]) ba->SetBit(i);
+                    return ba;
+                  } ), py::arg("vec"))
+    .def("__str__", &ToString<BitArray>)
+    .def("__len__", &BitArray::Size)
+    .def("__getitem__", [] (BitArray & self, int i)
+                                         {
+                                           if (i < 0 || i >= self.Size())
+                                             throw py::index_error();
+                                           return self.Test(i);
+                                         }, py::arg("pos"), "Returns bit from given position")
+    .def("__setitem__", [] (BitArray & self, int i, bool b)
+                                         {
+                                           if (i < 0 || i >= self.Size())
+                                             throw py::index_error();
+                                           if (b) self.SetBit(i); else self.Clear(i);
+                                         }, py::arg("pos"), py::arg("value"), "Clear/Set bit at given position")
+
+    .def("__setitem__", [] (BitArray & self, py::slice inds, bool b)
+                                         {
+                                           size_t start, step, stop, n;
+                                           if (!inds.compute(self.Size(), &start, &stop, &step, &n))
+                                             throw py::error_already_set();
+
+                                           if (start == 0 && n == self.Size() && step == 1)
+                                             { // base branch
+                                               if (b)
+                                                 self.Set();
+                                               else
+                                                 self.Clear();
+                                             }
+                                           else
+                                             {
+                                               if (b)
+                                                 for (size_t i=0; i<n; i++, start+=step)
+                                                   self.SetBit(start);
+                                               else
+                                                 for (size_t i=0; i<n; i++, start+=step)
+                                                   self.Clear(start);
+                                             }
+                                         }, py::arg("inds"), py::arg("value"), "Clear/Set bit at given positions")
+
+    .def("__setitem__", [](BitArray & self,  IntRange range, bool b)
+      {
+        if (b)
+          for (size_t i : range)
+            self.SetBit(i);
+        else
+          for (size_t i : range)
+            self.Clear(i);
+      }, py::arg("range"), py::arg("value"), "Set value for range of indices" )
+
+    .def("NumSet", &BitArray::NumSet)
+    .def("Set", [] (BitArray & self) { self.Set(); }, "Set all bits")
+    .def("Set", &BitArray::SetBit, py::arg("i"), "Set bit at given position")
+    .def("Clear", [] (BitArray & self) { self.Clear(); }, "Clear all bits")
+    .def("Clear", [] (BitArray & self, int i)
+                                   {
+                                       self.Clear(i);
+                                   }, py::arg("i"), "Clear bit at given position")
+
+
+    .def(py::self | py::self)
+    .def(py::self & py::self)
+    .def(py::self |= py::self)
+    .def(py::self &= py::self)
+    .def(~py::self)
+    ;
+
   py::class_<Flags>(m, "Flags")
     .def(py::init<>())
     .def("__str__", &ToString<Flags>)
diff --git a/tests/pytest/test_bitarray.py b/tests/pytest/test_bitarray.py
new file mode 100644
index 00000000..ed3d6fd8
--- /dev/null
+++ b/tests/pytest/test_bitarray.py
@@ -0,0 +1,35 @@
+from pyngcore import BitArray
+
+def test_bitarray():
+    a = BitArray(498)
+    assert len(a) == 498
+
+    a.Set()
+    for b in a:
+        assert b == True
+
+    a.Clear(23)
+    assert a[22] == True
+    assert a[23] == False
+    assert a[24] == True
+
+    a.Clear()
+    for b in a:
+        assert b == False
+
+    a.Set(23)
+    assert a[22] == False
+    assert a[23] == True
+    assert a[24] == False
+
+    a.Clear()
+    a[100:200:9] = True
+    for i in range(len(a)):
+        assert a[i] == bool(100<=i and i<200 and i%9==100%9)
+
+    ac = ~a
+
+    for b,bc in zip(a,ac):
+        assert b == (not bc)
+
+