diff --git a/nmigen/_toolchain.py b/nmigen/_toolchain/__init__.py
similarity index 100%
rename from nmigen/_toolchain.py
rename to nmigen/_toolchain/__init__.py
diff --git a/nmigen/_yosys.py b/nmigen/_toolchain/yosys.py
similarity index 99%
rename from nmigen/_yosys.py
rename to nmigen/_toolchain/yosys.py
index e84da53..c223306 100644
--- a/nmigen/_yosys.py
+++ b/nmigen/_toolchain/yosys.py
@@ -23,7 +23,7 @@ try:
 except ImportError:
     importlib_resources = None
 
-from ._toolchain import has_tool, require_tool
+from . import has_tool, require_tool
 
 
 __all__ = ["YosysError", "YosysBinary", "find_yosys"]
diff --git a/nmigen/back/cxxrtl.py b/nmigen/back/cxxrtl.py
index 38cb41b..f7c18ec 100644
--- a/nmigen/back/cxxrtl.py
+++ b/nmigen/back/cxxrtl.py
@@ -1,4 +1,4 @@
-from .._yosys import *
+from .._toolchain.yosys import *
 from . import rtlil
 
 
diff --git a/nmigen/back/verilog.py b/nmigen/back/verilog.py
index 1d2cb4a..31db02b 100644
--- a/nmigen/back/verilog.py
+++ b/nmigen/back/verilog.py
@@ -1,4 +1,4 @@
-from .._yosys import *
+from .._toolchain.yosys import *
 from . import rtlil