Shelltown is a neighborhood located within Southeast San Diego, approximately 5 minutes from downtown San Diego by car and 25 minutes by bicycle. It is bordered by National City on the south, Interstate 5 and Barrio Logan on the west, 43rd Avenue on the east, and Gamma Court and the neighborhood of Southcrest on the north. Prior to the 1980s the northern border of Shelltown was National Ave and many residents still consider that the northern border.

Southeast San Diego refers to the southeastern portion of the City of San Diego, including the neighborhoods south of State Route 94 and east of Downtown San Diego. Southeast San Diego has no official definition, but it may be considered coterminous with three official planning areas: Skyline-Paradise Hills, Encanto Neighborhoods, and Southeastern.