Lagoinha is a municipality in the eastern part of the state of São Paulo, Brazil. It is part of the Metropolitan Region of Vale do Paraíba e Litor…Lagoinha is a municipality in the eastern part of the state of São Paulo, Brazil. It is part of the Metropolitan Region of Vale do Paraíba e Litoral Norte. The population is 4,889 in an area of 255.47 km². The elevation is 913 m.