In 1899, the United States Department of War conducted a census of Puerto Rico finding that the population of San Lorenzo barrio was 884.

Clandestine car races took place in San Lorenzo for many years until an accident on July 18, 1998, claimed the lives of five people.

[13] San Lorenzo in Morovis was one of the areas of Puerto Rico heavily impacted by Hurricane Maria on September 20, 2017, with washed away bridges and loss of power for months.

[14] San Lorenzo was left isolated when Hurricane Maria washed away their main bridge with the PR-567 highway, into and out of the barrio.

The old road always being washed by the river, was at times passable and was being used by residents, (including school buses), until the construction of a temporary bridge was completed in April, 2018.