Use the Additions -> Highlight US County, or Additions -> Highlight US Zip Code to color any zip code or county in the US.
For Zip Codes, you can either specify a five digit zip code, or click on the map to get zip codes for locations.
For Counties, select a state and county.
As all highlighted regions in ZeeMaps, counties and zip codes regions have a boundary and fill, each of which can be customized for color, etc.
Once you’ve created a region, you can make changes to it by accessing your map as Admin and then click on a region to modify it. In the case of countries, states, counties, cities, or zip code, you can change the boundary and fill coloring at any time. For hand-drawn regions, you can also change the shape. For radius regions, you can additionally change the size and location.
For example, below is a map of Los Angeles with the famous 90210 (Beverly Hills) zip code highlighted.
The highlighted regions work both on the interactive maps and the static images, as shown in the image below.