Ermesinde is a civil parish in the municipality (concelho) of Valongo, in continental Portugal, 9 kilometres (5.6 mi) northeast of Porto.

[2] It is the smallest by area, and the densest by population (approximately 5000 inhabitants per kilometer square).

Initially a riverside community, named São Lourenço de Asmes, it developed as the result of the settlement of railworkers, involved in the construction of the railway.

The station that was constructed in this parish eventually developed and surpassed in the transit of the older São Lourenço de Asmes.

Ermesinde became a formal junction of the Portuguese railway network, becoming the start link along the Douro railway line to Pocinho In 1910, following the 5 October 1910 revolution, the parish officially adopted the new name.