La Línea de la Concepción (Spanish pronunciation: [la ˈlinea ðe la konθepˈθjon], more often referred to as La Línea) is a municipality of Spain belonging to the province of Cádiz, Andalusia.
The city lies on the sandy isthmus which is part of the eastern flank of the Bay of Gibraltar, and it limits with the Gibraltar–Spain border to the south. La Línea has close economic and social links with the British overseas territory of Gibraltar.
The first dwellings, which date back to the 18th century, were behind the Spanish lines, being part of the municipality of San Roque until 1870, when La Línea became a standalone municipality.
The people of La Línea have traditionally found work in Gibraltar, from the days in the 18th century when Gibraltar was an important naval port.