Together with Segundo, Tercero, Cuarto, Quinto, and Sexto, Primero is one of the municipality's original six core urban barrios.

The communities of Ponce de Leon, Los Maestros, Mariani, and Pedro J. Rosaly are located in Barrio Primero.

Primero is home to Ponce City Hall on its northeastern end.

The Dora Colón Clavell Urban Park, is also found in Barrio Primero.

The historic, NRHP-listed, Rosaly-Batiz House, Residencia Zaldo de Nebot on 27 Marina Street, and the Missionary Society of the Methodist Episcopal Church on 132 Villa Street, are also in Barrio Primero.