The closure followed a successful campaign to halt the use of the neighboring island of Vieques for war games and brought what some saw as a symbolic end to the Caribbean island's century-long life as a U.S. military colony.
"This is the lowering of the U.S. flag over Puerto Rico," said Puerto Rico Sen. Miriam Ramirez de Ferrer. "Besides losing material things, this will have an emotional toll."
Puerto Rico, a U.S. territory, once hosted several U.S. military bases and in recent years Roosevelt Roads was the largest. The Army's Ft. Buchanan remains open, but most observers say it probably will be shuttered in 2005 during the next round of base closings.
The naval base, which sprawls across 8,600 acres on Puerto Rico's eastern coast in the town of Ceiba, was estimated to pump some $300 million annually into the island's economy.
Last year, about 2,500 enlisted personnel lived on the base, along with an equal number of dependents. The base also contracted out hundreds of jobs to local residents.
The most immediate impact of the closure has been in the housing market. Officials say about 3,000 units surrounding the base are now surplus.
"We have lost a lot of base jobs, and a lot of people from the base who used to come to town to eat have stopped," Ceiba Mayor Gilberto Camacho said. "But this is not a ghost town."
The Navy decided to pull the plug on the base in May 2003 after it was forced to abandon its bombing range on Vieques, a key site for U.S. war games for about 60 years.
Demonstrators launched a protest campaign against the military after an errant bomb killed a civilian security guard on Vieques in 1999.
Officials said keeping Roosevelt Roads open without the Vieques training ground would be a drain on taxpayer dollars.
Despite the economic blow the closing of the 60-year-old base represents, Puerto Rican officials said redevelopment presented opportunities. A local group is working on a plan that will call for construction of hotels, tourism projects, and a science and technology park.
About 3,000 acres of the base will be set aside as a nature refuge or dedicated to ecotourism.
The Navy will own the land until it is transferred to the local government, which could take 10 years.