Route 420 or Highway 420 may refer to:
Australia Bass Highway (Victoria) South Gippsland Freeway South Gippsland Highway Bass Highway Phillip Island Road
Canada Ontario Highway 420 New Brunswick Route 420 Newfoundland and Labrador Route 420
Ireland R420 road
Japan Japan National Route 420
Norway Norwegian County Road 420
Spain N-420
United Kingdom
A420 road (Bristol to Oxford)
United States Interstate 420 (two unbuilt freeways) U.S. Route 420 Florida State Road 420 (former) County Road 420 (Orange County, Florida) Louisiana Highway 420 Indiana State Road 420 (now Interstate 94). New Mexico State Road 420 New York State Route 420 Ohio State Route 420 Pennsylvania Route 420 Puerto Rico Highway 420 South Carolina Highway 420 Tennessee State Route 420 Farm to Market Road 420 Virginia State Route 420 Kentucky State Route 420