Urban areas include both "urbanized areas," which are densely developed areas with a population of at least 50,000, and "urban clusters," which have a population of greater than 2,500 but less than 50,000. For more information, please see the link provided.
urban_areas(cb = FALSE, year = NULL, ...)If cb is set to TRUE, download a generalized (1:500k) cartographic boundary file. Defaults to FALSE (the most detailed TIGER/Line file).
the data year (defaults to 2016).
arguments to be passed to the underlying `load_tiger` function, which is not exported.
Options include refresh, which specifies whether or not to re-download shapefiles
(defaults to FALSE).
http://www2.census.gov/geo/pdfs/maps-data/data/tiger/tgrshp2015/TGRSHP2015_TechDoc.pdf
Other metro area functions: combined_statistical_areas,
core_based_statistical_areas,
metro_divisions, new_england