The following highways are numbered 173:
Canada Prince Edward Island Route 173 Quebec Route 173
India National Highway 173 (India)
Ireland R173 road
Japan Japan National Route 173
Korea, South Iksan–Pyeongtaek Expressway Branch
Philippines National Route 173 (Philippines)
United Kingdom road B173 road
United States Alabama State Route 173 Arizona State Route 173 (former) California State Route 173 Connecticut Route 173 Florida State Road 173 Georgia State Route 173 Illinois Route 173 Iowa Highway 173 K-173 (Kansas highway) Kentucky Route 173 Louisiana Highway 173 Maine State Route 173 Maryland Route 173 M-173 (Michigan highway) (former) Missouri Route 173 New Jersey Route 173 New Mexico State Road 173 New York State Route 173 Ohio State Route 173 Oregon Route 173 Pennsylvania Route 173 South Carolina Highway 173 Tennessee State Route 173 Texas State Highway 173 Texas State Highway Loop 173 Farm to Market Road 173 (Texas) Utah State Route 173 Virginia State Route 173 Washington State Route 173 Wisconsin Highway 173 Wyoming Highway 173 Territories Puerto Rico Highway 173