I am using windows10 64 bits, my os.name is 'nt', I used pip to install but its complaining about the spatialindex_c.dll

 File "C:\Users\Bachir\AppData\Local\Temp\pip-build-td64lrth\rtree\rtree\core.py", line 101, in <module>
   raise OSError("could not find or load spatialindex_c.dll")
 OSError: could not find or load spatialindex_c.dll

I downloaded rtree-0.8.2 and then run python setup.py install and i have the same message

PS C:\Users\Bachir\documents\Python Scripts\Rtree-0.8.2> python setup.py install
Traceback (most recent call last):
File "setup.py", line 4, in <module>
import rtree
File "C:\Users\Bachir\documents\Python Scripts\Rtree-0.8.2\rtree\__init__.py", line 1, in <module>
from .index import Rtree
File "C:\Users\Bachir\documents\Python Scripts\Rtree-0.8.2\rtree\index.py", line 6, in <module>
from . import core
File "C:\Users\Bachir\documents\Python Scripts\Rtree-0.8.2\rtree\core.py", line 101, in <module>
raise OSError("could not find or load spatialindex_c.dll")
OSError: could not find or load spatialindex_c.dll
PS C:\Users\Bachir\documents\Python Scripts\Rtree-0.8.2>  

I donwloaded the spatialindex dll files ' libspatialindex-1.8.1-win-msvc-2010-x64-x32.zip ' . this file contain both 32 and 64 bits , unzip and put in the installation folder, when installing using python setuo.py install it still complaining about the spatialindex dll file

3 Answers 3


Please, look at How can I install pyproj into arcpy?

1) the RTree module needs to be compiled with a version of libspatialindex installed in the system (your computer) and not simply adding spatialindex dll after
2) Windows has no compiler by default as in Linux or Mac OS X therefore you cannot install RTree with pip or setup.py install
3) in the Python Package Index page of RTree, bellow Download there is specified

Windows binaries http://www.lfd.uci.edu/~gohlke/pythonlibs/#rtree

The files are Rtree-0.8.2-cp27-none-win32.whl and Rtree-0.8.2-cp27-none-win_amd64.whl

To install a whl file, download the file and

pip install Rtree-0.8.2-cp27-none-....whl (32 or 64)
  • Rtree-0.8.2-cp27-none-win32.whl is not supported on python34 platfom
    – bhalitim
    Feb 6, 2016 at 16:58
  • Then you need to compile Rtree with a version of libspatialindex but I cannot help you because I do not use Windows
    – gene
    Feb 6, 2016 at 18:13
  • Is it possible to include this downloaded wheel in your own package and to have pip install it from there? Right now I can't specify rtree as a dependency... Jan 7, 2020 at 14:21

I had the same problem and solved it by changing the core.py file in Rtree in


and changed this line :

rt = _load_library('spatialindex_c.dll', ctypes.cdll.LoadLibrary)

by this :

rt = _load_library('spatialindex_c-64.dll', ctypes.cdll.LoadLibrary)

For users using Anaconda on Windows 64 bit machines:

Rtree plays an important role in Python GIS packages like geopandas, proj, pyproj etc.

I had same issue while importing geopandas in Jupyter notebook and I found out it was caused by RTree.

Now the solution to this particular problem:

OSError: could not find or load spatialindex_c-64.dll

Do these steps:

  1. Update python in your conda environment only using conda-forge channel like: conda install -c conda-forge python==3.7.10 . If you don't know what version of python to use just use what I used. You will see conda updates your python as cpython

  2. Now update rtree again using conda install rtree. Don't provide any channel here.

You're done here.

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