diff --git a/toolchains/nextpnr.py b/toolchains/nextpnr.py
index d97c66a59..00b2a4f79 100644
--- a/toolchains/nextpnr.py
+++ b/toolchains/nextpnr.py
@@ -699,8 +699,17 @@ def __init__(self, rootdir):
 
     def configure(self):
         super().configure()
+
         self.tool_options['binary_path'] = self.toolchain_bin
 
+        nisp_data = os.path.join(
+            self.rootdir, 'env', 'interchange', 'devices', self.chip,
+            '{}_site_routability.json'.format(self.chip)
+        )
+
+        options = self.tool_options['nextpnr_options']
+        options['site-routing-graph'] = nisp_data
+
 
 class NextpnrXilinx(NextpnrGeneric):
     '''nextpnr Xilinx variant using Yosys for synthesis'''