High Quality Content by WIKIPEDIA articles! Río San Juan is a municipality in the María Trinidad Sánchez, province of the Dominican Republic. María Trinidad Sánchez is a province of the Dominican Republic. It was split from Samaná in 1959. The name commemorates a disginguished female soldier in the wars of independence. María Trinidad Sánchez was the first woman incarcerated and executed by Pedro Santana, a Dominican annexionist president. The following is a sortable table of the municipalities and municipal districts with population figures as of the 2008 census. Urban population are those living in the seats (cabeceras literally heads) of municipalities or of municipal districts. Rural population are those living in the districts (Secciones literally sections) and neighborhoods (Parajes literally places) outside of them.