The Maryland State Board of Education yesterday upheld a desegregation plan for Rosemary Hills Elementary in Silver Spring, a school with a high minority enrollment and the focal point of one of Montgomery County's most divisive debates over how to improve racial balance in its schools.

The state board found Montgomery school officials had "shown good faith" and had acted on "a reasonable basis" when they voted to reinstate a busing plan between Rosemary Hills and two schools in the predominantly white and affluent Chevy Chase area. The state board said the actions, which returned substantially to a busing plan dismantled last year, also met the county board's racial guidelines without placing an unfair burden on either minority or white students.

Roscoe Nix, president of the county's NAACP chapter, hailed the unanimous state action as a victory for minorities and the new Montgomery board majority that was swept into office in November and promised a keener sensitivity to racial policies than demonstrated by their predecessors. During their campaigns, the four new board members (on a seven-member board) had attacked an unsuccessful attempt by the old board to close Rosemary Hills, the centerpiece of the county's integration efforts for at least six years.

The plan the state board approved yesterday says students from the predominantly white areas that feed into Chevy Chase and North Chevy Chase elementary schools should attend Rosemary Hills for grades preschool through second. Children from the three schools would then attend either Chevy Chase or North Chevy Chase for the remaining four grades.

In announcing its decision yesterday, the state board called the new plan a more "reasonable attempt to deal equitably with the minority and majority students" than the old board's plan. The old board last year at first attempted to close Rosemary Hills, and when the state rejected that, closed two other schools in the area and divided students between Chevy Chase and Rosemary Hills. Half the students who lived in the Rosemary Hills area were assigned to a school other than Rosemary Hills for their entire elementary school years, according to school documents.

Chevy Chase community representatives, who liked that plan and submitted to the state affadavits from 31 Chevy Chase families saying they would enroll their children in private school rather than in kindergarten at Rosemary Hills, said the real fallout from yesterday's decision was yet to be seen.

"The board seems to underestimate just how frustrated people genuinely feel," said Diane Cross, a member of the Chevy Chase Parent Teacher Association. "Perhaps if the board makes a conscientious effort to make the educational program at Rosemary Hills work, which I believe they will, then maybe some people will show up. But I really don't believe many will . . . It is quite clear that nobody gives two hoots about Chevy Chase."

During their appeal, Chevy Chase parents argued they had tried the pairing with Rosemary Hills for six years but that mixing students from wide economic and cultural backgrounds posed too many educational problems. In addition, they claimed Chevy Chase already was a well-integrated school.

The state board, however, rejected these arguments and criticized the parents who said they would not take part in the integration plan.

Board president Blair Ewing, who led the fight to save Rosemary Hills last year when he was one of two dissenters on the board, yesterday welcomed the decision and said that the question all along has not been whether Chevy Chase was now an integrated school, but whether the burden of integration was a fair one.

Yesterday's decision, he said, would help the county regain its reputation for being progressive on racial issues. During the battle over Rosemary Hills, attention focused on the apparent dichotomy between the county's traditionally liberal record on social issues and the fight over busing.

Board member Suzanne Peyser, one of two members from the old board still on the new one, disagreed with Ewing, saying that yesterday's decision would result in a dramatic exodus of white parents.

"It's a bad day for the school system. This busing is driving people out of public schools," Peyser said.

Marian Greenblatt, the other holdover member who first gained attention when she opposed the Rosemary Hills pairing at a Parent Teacher Association meeting seven years ago in her neighborhood, concurred with Peyser.

"This is a great injustice to the children in these areas," Greenblatt said.

The state board yesterday also voted to uphold the local board's decision to close Northwood High School, Lake Normandy Elementary and Georgetown Hill Elementary.