diff --git a/graphblas/__init__.py b/graphblas/__init__.py
index a9895cb6a..63110eeeb 100644
--- a/graphblas/__init__.py
+++ b/graphblas/__init__.py
@@ -39,6 +39,7 @@ def get_config():
 backend = None
 _init_params = None
 _SPECIAL_ATTRS = {
+    "MAX_SIZE",  # The maximum size of Vector and Matrix dimensions (GrB_INDEX_MAX + 1)
     "Matrix",
     "Recorder",
     "Scalar",
@@ -205,6 +206,10 @@ def _load(name):
     if name in {"Matrix", "Vector", "Scalar", "Recorder"}:
         module = _import_module(f".core.{name.lower()}", __name__)
         globals()[name] = getattr(module, name)
+    elif name == "MAX_SIZE":
+        from .core import lib
+
+        globals()[name] = lib.GrB_INDEX_MAX + 1
     else:
         # Everything else is a module
         globals()[name] = _import_module(f".{name}", __name__)
diff --git a/graphblas/tests/test_core.py b/graphblas/tests/test_core.py
index 003affc6c..3586eb4a8 100644
--- a/graphblas/tests/test_core.py
+++ b/graphblas/tests/test_core.py
@@ -90,3 +90,7 @@ def test_packages():
     assert (
         pkgs == pkgs2
     ), "If there are extra items on the left, add them to pyproject.toml:tool.setuptools.packages"
+
+
+def test_index_max():
+    assert gb.MAX_SIZE == 2**60  # True for all current backends
diff --git a/scripts/test_imports.sh b/scripts/test_imports.sh
index cc989ef06..6ce88c83e 100755
--- a/scripts/test_imports.sh
+++ b/scripts/test_imports.sh
@@ -13,7 +13,7 @@ if ! python -c "from graphblas.select import tril" ; then exit 1 ; fi
 if ! python -c "from graphblas.semiring import plus_times" ; then exit 1 ; fi
 if ! python -c "from graphblas.unary import exp" ; then exit 1 ; fi
 if ! (for attr in Matrix Scalar Vector Recorder agg binary dtypes exceptions \
-  init io monoid op select semiring tests unary ss viz
+  init io monoid op select semiring tests unary ss viz MAX_SIZE
   do echo python -c \"from graphblas import $attr\"
     if ! python -c "from graphblas import $attr"
       then exit 1