The water parting is about twice as far from the north coast as it is from the south coast, the rainfall is greater on the north slope, and the principal rivers - Rio Loiza, Rio de la Plata, Rio Manati and Rio Arecibo are on the north side.
The principal towns, with the population of each in 1910, are: San Juan, 48,716; Ponce, 35,027; Mayaguez, 16,591; Arecibo, 9612.
ARECIBO, a city and port on the north coast of Porto Rico, at the mouth of a small stream called the Rio Grande de Arecibo, and contiguous to one of the most fertile regions of the island.
Arecibo is connected with San Juan, Mayaguez and Ponce by railway.
Arecibo was founded in 1788.