WASHINGTON — The population of Maine will be a bit larger in the 1990 census because of a change in the way overseas military personnel are counted.

Under the old system, the nation’s 1 million overseas military personnel were classified as residents in the state where their last home-side duty assignment base was located.

That provision favored coastal states, where overseas personnel disembarked for overseas assignments, prompting Midwestern lawmakers to seek a change.

As a result of their legislation, the 1990 Census will list military personnel as residents of their “home of record.”

The new method of counting will cause some states to lose and others to gain significant numbers of residents, an important factor in the allocation of federal funds and the upcoming redistricting of Congress.

Maine is one of the states that will gain population as a result of the census change.

Under the old system, the state would be listed as home for 2,578 military personnel, most of whom disembarked from Loring Air Force Base and the Brunswick Naval Air Station for overseas assignments.

As a result of the change, which took effect Dec. 31, 1989, Maine loses those 2,578 non-resident military personnel, but gets credit for 4,044 Maine residents who shipped out from bases in other states for overseas assignments.

The effect is a gain of 1,466 people in the new census.

The biggest gainer was Wisconsin, which gained 12,000 in population. California and New York were the biggest losers, giving up 55,000 and 30,000 residents, respectively, in the 1990 Census.

A Pentagon official indicated that three options were considered before enactment of the census count change. They were last duty station, home of record, or the state they list as home for income tax purposes.

Originally, it was indicated, the Commerce Department opted for last duty station. But Midwestern members of Congress stepped in and introduced bills to require the count by home of record instead.

Commerce agreed to the change without need for legislation.

Assigning people to the state where they list themselves as residents for income tax purposes apparently was not seriously considered, since many opt for states with low or no income taxes.

Pentagon officials said that the home of record provision has problems, since the service people may not have been there in many years. But it tends to distribute people more evenly across the nation, based on where they lived when they joined the service.