diff --git a/README.md b/README.md
index bdcc1a0a6..cab7992f1 100644
--- a/README.md
+++ b/README.md
@@ -25,6 +25,8 @@ After this is done simply follow the directions as per a source build.
 
 ### Building from Source
 
+For detailed MacOS with Homebrew instructions, see section below
+
 Assuming that you built your own mapnik from source, and you have run `make install`. Set any compiler or linking environment variables as necessary so that your installation of mapnik is found. Next simply run one of the two methods:
 
 ```
@@ -53,6 +55,46 @@ If you need Pycairo, make sure that PYCAIRO is set to true in your environment o
 PYCAIRO=true python setup.py develop
 ```
 
+### Building on MacOS Catalina with Homebrew: use mapnik/master and python-mapnik-master
+
+On MacOS Catalina with Homebrew, the homebrew's mapnik version (3.0) conflicts with the boost version (>1.73). 
+
+Its much easier to compile mapnik 4.0 from `mapnik/master`, and compile `python-mapnik` against that.
+
+#### First: setup homebrew packages
+
+```
+# note: boost needs to be >= 1.73, make sure boost@1.73 is linked too
+brew install boost boost-python3 sqlite gdal cairo python@3.8
+brew upgrade boost boost-python3 sqlite gdal cairo python@3.8
+brew link boost
+
+# We're build a custom mapnik 4, uninstall the stale 3.x version in homebrew:
+brew uninstall mapnik
+```
+
+#### Second: build `mapnik/master`
+
+Setting the `PYTHON=python2` env var is important, an older fork of SConstruct is embedded in mapnik source, which will not work with `python` if its linked to `python3` as on some MacOS systems. Passing a path to sqlite3 will select the homebrew version instead of the MacOS system version (which doesn't include support for sqlite extensions and will break the mapnik compile).
+
+```
+brew install boost 
+git clone https://github.com/mapnik/mapnik ; cd mapnik
+git submodule update --init
+PYTHON=python2 ./configure. SQLITE_INCLUDES=/usr/local/opt/sqlite3/include
+make
+make install
+```
+
+#### Finally: build `python-mapnik/master`
+
+Homebrew includes the python version in the libboost_python38.dylib name, which is not autodetected, and must be explicitly referenced:
+
+```
+git clone https://github.com/mapnik/python-mapnik ; cd python-mapnik
+BOOST_PYTHON=boost_python38 python3 setup.py install
+```
+
 ### Building against Mapnik 3.0.x
 
 The `master` branch is no longer compatible with `3.0.x` series of Mapnik. To build against Mapnik 3.0.x, use [`v3.0.x`](https://github.com/mapnik/python-mapnik/tree/v3.0.x) branch.