Estádio do Junco, Football stadium in Sobral, Brazil.

Estádio do Junco, also called Juncão, is a football ground in the Junco neighbourhood of Sobral, Ceará, with a capacity of 10,000. Its official name, Estádio Municipal Plácido Aderaldo Castelo, honours a former state governor. The ground has floodlights, an electronic scoreboard and turnstiles brought from Fortaleza's Castelão in 2011, plus a press room and a climatised referees' changing room.

The stadium was inaugurated in 1969 under Mayor Jerônimo Medeiros Prado, who named it after former state governor Plácido Aderaldo Castelo. The opening match pitted Guarany de Sobral against América from Fortaleza. Floodlights followed a few years later, ordered by Lewan Albuquerque Lustosa, president of Sobral's sports association, during the 1973–1977 administration of Mayor José Parente Prado.

The stadium is closely tied to local football club Guarany de Sobral and has served the city as a gathering place for major matches for decades. Here fans and players come together for championships and derbys that hold deep meaning for the community.

The stadium sits in the Junco neighbourhood of Sobral and serves as the home ground of Guarany Sporting Club. It reopened on 5 July 2025 after about a year closed for repairs, with new paint, LED floodlights and a reworked stand. Look for the electronic turnstiles and scoreboard transferred from Fortaleza's Castelão in 2011.

In 2000 this was the first venue to host a Campeonato Cearense final outside the state capital, marking a turning point in the region's sports history. The event demonstrated that major competitions could be successfully held in smaller cities.