Cb 2014 Us Zcta510 500k

The cartographic boundary files are simplified representations of selected geographic areas from the Census Bureau’s MAF/TIGER geographic database. These boundary files are specifically designed for small scale thematic mapping.

Generalized boundary files are clipped to a simplified version of the U.S. outline. As a result, some off-shore areas may be excluded from the generalized files. For more details about these files, please see our Cartographic Boundary File Description page.

From https://www.census.gov/geo/maps-data/data/gazetteer2010.html

From https://www.census.gov/geo/maps-data/data/gazetteer2010.html

Linestrings for coastlines. Long linestrings are split into smaller chunks that are easier and faster to work with.