This resource is a member of a series. The TIGER/Line shapefiles and related database files (.dbf) are an extract of selected geographic and cartographic information from the U.S. Census Bureau's Master Address File / Topologically Integrated Geographic Encoding and Referencing (MAF/TIGER) System (MTS). The MTS represents a seamless national file with no overlaps or gaps between parts, however, each TIGER/Line shapefile is designed to stand alone as an independent data set, or they can be combined to cover the entire nation. Census tracts are small, relatively permanent statistical subdivisions of a county or equivalent entity and were defined by local participants as part of the 2020 Census Participant Statistical Areas Program. The Census Bureau delineated the census tracts in situations where no local participant existed or where all the potential participants declined to participate. The primary purpose of census tracts is to provide a stable set of geographic units for the presentation of census data and comparison back to previous decennial censuses. Census tracts generally have a population size between 1,200 and 8,000 people, with an optimum size of 4,000 people. When first delineated, census tracts were designed to be homogeneous with respect to population characteristics, economic status, and living conditions. The spatial size of census tracts varies widely depending on the density of settlement. Physical changes in street patterns caused by highway construction, new development, and so forth, may require boundary revisions. In addition, census tracts occasionally are split due to population growth, or combined because of substantial population decline. Census tract boundaries generally follow visible and identifiable features. They may follow legal boundaries such as minor civil division or incorporated place boundaries in some states and situations to allow for census tract-to-governmental unit relationships where the governmental boundaries tend to remain unchanged between censuses. State and county boundaries always are census tract boundaries in the standard Census Bureau geographic hierarchy. In a few rare instances, a census tract may consist of noncontiguous areas. These noncontiguous areas may occur where the census tracts are coextensive with all or parts of legal entities that are themselves noncontiguous.

A summary of the demographic information and additional samples collected from 96 necropsied, free-ranging red-eared sliders (Trachemys scripta elegans) from Cook County, Illinois.

To characterize the number of oculofacial plastic surgeons (OPS) per county in the United States (U.S.). The 2021 public databases of the American Society of Ophthalmic Plastic and Reconstructive Surgery and the American Academy of Ophthalmology were used to identify all OPS in the U.S. Surgeon practice location was used to determine per capita physician density by county. A total of 1184 OPS in the U.S. were identified. Three hundred forty-eight counties were served by at least one OPS whereas 2795 counties (89%), and two states, North Dakota and Wyoming, had no OPS. The average ratio of OPS to 100,000 population was 0.3572 (1 per 279,955). Of the counties with at least one OPS, the average was 0.5860 surgeons per 100,000 population (1 per 170,648), ranging from 0.0705 (1 per 1,418,440) to 11.26 (1 per 8,881) per 100,000. The counties with the greatest OPS density were Pitkin County, CO (1 per 8,881), San Juan County, WA (1 per 17,580), and Montour County, PA (1 per 18,231). Counties with the lowest density of those with at least one OPS were Bronx County, NY (1 per 1,418,238), San Bernardino County, Ca (1 per 1,090,037), and Gwinnett County, GA (1 per 936,329). The counties with the most OPS were Los Angeles County, CA (46), New York County, NY (38), and Cook County, IL (25). Geographic disparities in OPS distribution exist in the U.S. Future investigations of OPS supply according to population and other characteristics for demand may be useful.