diff --git a/packages/cosmic-swingset/.gitignore b/packages/cosmic-swingset/.gitignore
index 8b774430eb3..e865f9cdfac 100644
--- a/packages/cosmic-swingset/.gitignore
+++ b/packages/cosmic-swingset/.gitignore
@@ -85,7 +85,6 @@ typings/
 
 # next.js build output
 .next
-ag-cosmos-chain-state.json
 lib/git-revision.txt
 agoric/
 /binding.gyp
diff --git a/packages/cosmic-swingset/Makefile b/packages/cosmic-swingset/Makefile
index 899f697ba03..c291773f302 100644
--- a/packages/cosmic-swingset/Makefile
+++ b/packages/cosmic-swingset/Makefile
@@ -27,7 +27,6 @@ all: build-cosmos install
 
 scenario0-setup:
 	rm -rf ~/.ag-chain-cosmos
-	rm -f ag-cosmos-chain-state.json
 	python3 -mvenv ve3
 	ve3/bin/pip install setup-solo/
 
@@ -49,7 +48,6 @@ scenario1-run-client:
 AGC = ./lib/ag-chain-cosmos
 scenario2-setup: build-cosmos
 	rm -rf ~/.ag-chain-cosmos
-	rm -f ag-cosmos-chain-state.json
 	$(AGC) init scenario2-chain --chain-id=$(CHAIN_ID)
 	rm -rf t1
 	mkdir t1
@@ -148,7 +146,7 @@ start-ag-solo:
 	cd t1 && ../bin/ag-solo start
 
 show-local-gci:
-	@./calc-gci.js ~/.ag-cosmos-chain/config/genesis.json
+	@./calc-gci.js ~/.ag-chain-cosmos/config/genesis.json
 
 set-local-gci-ingress:
 	set -e; \
diff --git a/packages/cosmic-swingset/lib/ag-chain-cosmos b/packages/cosmic-swingset/lib/ag-chain-cosmos
index a564e7e271f..557556d5f67 100755
--- a/packages/cosmic-swingset/lib/ag-chain-cosmos
+++ b/packages/cosmic-swingset/lib/ag-chain-cosmos
@@ -8,10 +8,33 @@ const BEGIN_BLOCK = 'BEGIN_BLOCK';
 const DELIVER_INBOUND = 'DELIVER_INBOUND';
 const AG_COSMOS_INIT = 'AG_COSMOS_INIT';
 
-// TODO: use the 'basedir' pattern, or find the cosmos state directory
-// (~/.ag-chain-cosmos ?), or something anything better than scribbling
-// into the current directory.
-const stateFile = 'ag-cosmos-chain-state.json';
+// TODO: use the 'basedir' pattern
+
+// Try to determine the cosmos chain home.
+function getFlagValue(flagName, deflt) {
+  let flagValue = deflt;
+  const envValue = process.env[`AG_CHAIN_COSMOS_${flagName.toUpperCase()}`];
+  if (envValue !== undefined) {
+    flagValue = envValue;
+  }
+  const flag = `--${flagName}`;
+  const flagEquals = `--${flagName}=`;
+  for (let i = 0; i < process.argv.length; i += 1) {
+    const arg = process.argv[i];
+    if (arg === flag) {
+      i += 1;
+      flagValue = process.argv[i];
+    } else if (arg.startsWith(flagEquals)) {
+      flagValue = arg.substr(flagEquals.length);
+    }
+  }
+  return flagValue;
+}
+
+// We try to find the actual cosmos state directory (default=~/.ag-chain-cosmos), which
+// is better than scribbling into the current directory.
+const cosmosHome = getFlagValue('home', `${process.env.HOME}/.ag-chain-cosmos`);
+const stateFile = `${cosmosHome}/data/ag-cosmos-chain-state.json`;
 
 const { launch } = require('./launch-chain');
 const path = require('path');