Mildred Obear is packing her belongings and getting ready to move out of her house on 19th Street NW into an apartment elsewhere. When she vacates the house - sometime in the next few weeks - no one will move into the house or the block where it stands.

Obear is probably the last person who will ever live on Square 121, a block bounded by 19th, 20th, F and G streets. In 1970, according to the census that year, there were 50 residents and 20 housing units on Square 121.

Shortly after Obear leaves her 170-year-old home, it will be moved to the 600 block of 21st Street NW to make way for a large office building to be constructed by George Washington University and occupied by the World Bank. Obear's house, in its new location, will be used for university purposes.

Obear's fight to stay in her home - a fight she reluctantly ended last June when she sold her house to George Washington - was only one skirmish in a long struggle between the residential neighborhood and the university.

The struggle is not over by any means, according to residents of the area. But the victories seem to be going to the university and to international organizations.

The GWU area is bounded by Pennsylvania Avenue and K Street on the north, 19th Street on the east, E Street and Virginia Avenue on the south and 23rd Street on the west. According to a study by the Municipal Planning Office (MPO), the population of the area dropped about 25 percent between 1960 and 1970 - from 4,495 to 3,388. The number of housing units dropped about 29 percent during the same period - from 3,209 to 2,291.

No current statistics have been compiled, but MPO sources said no new housing units have been built in the area and several residential buildings have been demolished or converted to dormitories or office buildings. As a result, the sources said, the area's population has continued to decline since the 1970 census.

Neighborhood activists - whose efforts are coordinated by the Foggy Bottom-West End Advisory Neighborhood Commission (ANC) - say they are not giving up the struggle. Moreover, they say the World Bank zoning decision, which will allow the office building to constructed on Square 121, was neither a total defeat for the neighborhood nor a total victory for GWU.

The university, in a decision announced in October, won preliminary approval for construction of he building which will be sold or leased to the World Bank. The agreement with the bank will allow the building to be returned to the university for its own use after about 30 years.

The building, however, will be smaller than the one the university wanted, will have a garden area open to the public and will have small shops on the ground floor. In addition, the F Street Club, a pre-Civil War home, and its garden will preserved. The university originally wanted to move the house but will keep it in place and design the new office building around it.

Obear agreed to sell her house that it after the university and preserve both her house and the house next door, which was willed to the university by its owner. Both houses, known as the Lenthall houses, built in 1808 by John Lenthall, as assistant to Capitol architect Benjamin Latrobe. To make way for the two Lenthall houses, the university has razed a house at 604 21st NW.

The erosion of housing stock in the G. W. D. neighborhood began shortly after the university moved into the area in 1912. The University took over townhouses used them for classrooms and offices and aventually razed them and put student unions, libraries, atheletic facilities and parking lots. Over the years, existing apartment buildings were bought and converted to dormitories.

At a zoning commission hearing on the World Bank building, James Molinelli, president of the West End Citizens Association, testified that in 1962 he had been forced to move from the Park Central apartments at 1900 F St. NW.

"I lived in the Park Central for over 14 years," he said at the hearing, "until GWU bought the property and evicted my family and 279 other familes to make room for a dormitory which is now called Thurston Hall."

Prompted by Molinelli's testimony, the zoning commission asked GWU for a list of university property purchases during the past 10 years, showing how many people had been displaced. Between and 1967 and 1977, the university listed purchases of 76 buildings and several parking lots and added that the buildings contained 454 active housing units when purchased. The university said the buildings currently contain 432 housing units - representing a total displacement of 22 housing units.

Since the list was submitted, several developments have taken place that further limit the available housing in the area:

The university has razed five 19th Century townhouses in the 1900 block of G Street to make way for the World Bank building.

A gift shop, on the south side of Washington Circle, with apartments above it and an adjacent townhouse on 23rd Street have been demolished to make way for a new medical school building.

Three buildings - one of them containing apartments - in the 2100 block of I Street have been demolished in preparation of construction of a new academic cluster.

A demolition permit has been obtained by the university for 2135 F St. NW, which was a boarding house.

The university has vacated three apartment buildings - the Guthridge at 2115 F St. NW, the Everglades at 2223 H St. NW, and Milton Hall at 2222 I St. NW - for conversion to dormitories. The buildings contained more than 300 apartments.

The Town House apartments at 601 19th St. NW, containing 180 apartments, have been demolished by the Organization of American States, which is constructing an office building on the site.

The Governor Shepherd apartments at 2121 Virginia Ave. NW have been bought by the Pan American Health Organization.

An apartment building at 2109 F St. NW was recently purchased by the university, which plans to replace the current tenants with students through a process of attrition.

The university campus master plan, approved by the National Capital Planning Commission in 1970, mapped out a campus bounded by 19th and 24th streets, F Street and Pennsylvania Avenue. According to the plan, the university is buying all available property within the area and pursuing a program of high-density construction. Buildings of architectural or historic interest are to be preserved when possible.

The plan specifies that "high-value frontage" - such as land along Pennsylvania Avenue currently used for commercial office space and the future site of the World Bank Building - be leased for revenue purposes and converted to university use when the buildings have paid for themselves.

University officials say this practice of using property to generate income helps the university stay in the black and keep tuition down. Neighborhood activists, however, say the university should not be in the real estate business and generally object to the master plan.

James Fennelly, president of a student group called the Committee for the Campus, said the committee plans to work toward getting university officials to revise the plan.

"There would only be about two townhouses left in the area if the plan were fully carried out," said Fennelly. "I'd like to see a plan that would reflect the needs of the university community not only in a financial way - a plan that would keep a mix of university, residential, and small stores. We want to keep GWU in the neighborhood, not separated from it."