Try these sample GeoJson URL
These URL can be saved as a GeoJson file
Socrata open data geojson URL format, Los Angeles Council District
https://data.lacity.org/api/geospatial/5v3h-vptv?method=export&format=GeoJSON
Arcgis online hub geojson URL format, Los Angeles Council District
https://opendata.arcgis.com/api/v3/datasets/76104f230e384f38871eb3c4782f903d_13/downloads/data?format=geojson&spatialRefId=4326&where=1%3D1
1. California Catalina Island Zoning
https://transparentgov.net/data/sample/california_Catalina_Island_zoning.geojson
2. Santa Monica, California (mixed line and point in a single geojson file)
https://transparentgov.net/data/sample/geojson/linePointMix.geojson
3. Alaska Solid Waste Sites
https://transparentgov.net/data/sample/alaska_Solid_Waste_Sites.geojson
4. Alaska Areas
https://transparentgov.net/data/sample/alaska_Areas.geojson
5. World Countries
https://transparentgov.net/data/sample/countries.geojson
Upload xxx.geojson file from your computer
GoogleMaps
https://transparentgov.net:3200/googlemaps93/upload