Description from the US Census Bureau: "The Census Bureau includes landmarks such as military installations in the MAF/TIGER database for locating special features and to help enumerators during field operations. The Census Bureau adds landmark features to the database on an as-needed basis and does not attempt to ensure that all instances of a particular feature are included. For additional information about area landmarks, please see Section 3.12, Landmarks (Area and Point)."
military(year = NULL, ...)the data year (defaults to 2020).
arguments to be passed to the underlying `load_tiger` function, which is not exported.
Options include class, which can be set to "sf" (the default) or "sp" to
request sf or sp class objects, and refresh, which specifies whether or
not to re-download shapefiles (defaults to FALSE).
This file does not include the three point landmarks identified as military installation features in the MAF/TIGER database. These point landmarks are included in the point landmark shapefile. Although almost all military installations have assigned 8-character National Standard (GNIS) codes, the Census Bureau has not loaded most of this data into the MAF/TIGER database. The 2020 military shapefiles contain few values in the ANSICODE field.
https://www2.census.gov/geo/pdfs/maps-data/data/tiger/tgrshp2020/TGRSHP2020_TechDoc_Ch3.pdf