Lajas (Spanish pronunciation: [ˈlaxas]) is a municipality of Puerto Rico located in southwestern Puerto Rico, on the southern coast of the island, bordering the Caribbean Sea, south of San Germán and Sabana Grande; east of Cabo Rojo; and west of Guánica. Lajas is spread over 11 barrios plus Lajas Pueblo (the downtown area and the administrative center of the city). It is part of the San Germán-Cabo Rojo Metropolitan Statistical Area.
Located at the Lajas Valley, the town was founded in 1883 by the Xueta Teodoro Jacome Pagan. Xuetes (Chuetas) were Majorcan Jews (Sephardi Catalan Jews). Some families changed their names from Jacome to the Castilian form Santiago (Saint James the Righteous). Jacome is the Mallorquin form of James (Ia'akov). Catalan Jews from Majorca were part of the early settlers in the South of (Boriken) (Puerto Rico).
Puerto Rico was ceded by Spain in the aftermath of the Spanish-American War under the terms of the Treaty of Paris of 1898 and became a territory of the United States. In 1899, the United States conducted its first census of Puerto Rico finding that the population of Lajas was 8,789.
The village of La Parguera is a popular tourist destination to see the famous Bahía Fosforescente (Phosphorescent Bay) and its keys and islet's.
People from the El Combate community in barrio Boquerón are known as mata con hacha ("those who kill with axes") based on folklore about a fight over the salinas, where those from Cabo Rojo fought with axes against people from the adjacent town of Lajas.