Hundreds of students will be shuffled to new schools next year as a result of boundary changes adopted late Tuesday for 21 of Loudoun County's 38 elementary schools.

The School Board's decisions brought an end to an emotional process necessitated by the opening of three new elementary schools in western Loudoun, Leesburg and northern Sterling.

Residents had suggested more than 150 plans, and hundreds attended community hearings on the issue as well as Tuesday night's meeting. Residents downloaded copies of alternative plans posted on the Loudoun County Public Schools Web site 23,000 times, schools spokesman Wayde B. Byard said.

In the end, however, board members set aside the plans developed by parents and the school system's staff and crafted their own solutions for boundaries in each area.

For eastern Loudoun, where one resident said the process had been "gut-wrenching," the board adopted a compromise plan devised by the two members who jointly represent the area, John A. Andrews II (Broad Run) and Candyce P. Cassell (Sugarland Run).

The two said their plan, which would move some children from Horizon Elementary School in the Cascades area to Algonkian and Potowmack elementaries, sought to limit crowding at the eight elementary schools in the area and meant that Horizon will be the only area school north of Route 7 to feed two middle schools.

The Andrews-Cassell plan made no changes to the boundaries of Sugarland Elementary, one of the county's most diverse schools. Under a plan recommended by Superintendent Edgar B. Hatrick III, the school's boundaries would have shifted to reduce the percentage of students who receive a free or reduced-price lunch, the number taking English as a second language and those with lower standardized test scores.

Harry F. Holsinger (Blue Ridge) said he could not support the Andrews-Cassell plan for this reason, citing figures showing that Sugarland's median score on the Stanford reading test will remain lower than other area schools. Holsinger and J. Warren Geurin (Sterling) abstained from the vote, while the board's other six members approved it.

"As a school becomes perceived as a low-performing school, you get into a vicious cycle of self-fulfilling prophesies. I'm worried we will create a school that is perceived as less than worthy," Holsinger said.

Andrews said he could not support busing students who might otherwise walk to a closer school just to even out test scores and demographics.

Some residents said the debate has created deep rifts among neighbors.

"This process has been absolutely gut-wrenching for the Horizon community," said Aimee Waltz, whose children will stay at Horizon but watch many friends leave the school. "I don't consider it a victory. I consider it an amputation."

In western Loudoun, the board adopted a plan that closely echoed one advanced by school staff several weeks ago, with some revisions. The plan will move some Purcellville children from Emerick Elementary to the new Mountain View Elementary. The Purcellville Town Council had presented a plan that would have allowed all children living inside the town's limits to continue attending Emerick Elementary. Contending that Purcellville's rural, small-town feel would be damaged if some town children attended the new Mountain View Elementary, the council and residents pushed the School Board to accept their "One Town, One School" plan. Other western towns, including Round Hill and Hamilton, also signed on to the Purcellville plan.

Town Manager Robert W. Lohr Jr. said staff used their firsthand knowledge of Purcellville's neighborhoods and were confident that all could fit at Emerick for the next five years.

But schools Planning Director Sam C. Adamo said his calculations showed that too many children lived in the town to fit at Emerick. "Their whole base is erroneous," Adamo said. "It's bogus data."

Lohr countered: "They're saying that, but no one is showing us where our numbers don't work. Let's take street by street, neighborhood by neighborhood." Holsinger told the board that experience has taught him to trust the school staff's numbers.

In Leesburg, the board adopted a plan proposed by Frederick F. Flemming (Leesburg), which differed in a few areas from a plan proposed by staff several weeks ago. Flemming said his plan leaves the boundaries for three of Leesburg's six existing elementary schools intact and makes only minor revisions to a fourth. He acknowledged that some residents of subdivisions slated to be moved from Tolbert Elementary School to Ball's Bluff Elementary School would be disappointed by his plan.

The board also adopted a timeline for replacing board member Patrick F. Chorpenning Jr. (Mercer), who resigned unexpectedly this month to take a job in Arizona. Their plans calls for them to advertise for volunteers or nominations. They will hold a public hearing Jan. 9 and vote on the matter on Jan. 16. The School Board has 45 days from Monday, the date of Chorpenning's resignation, to appoint a replacement until a successor is elected next November. If the board cannot reach a decision in the required 45 days, the Loudoun County Circuit Court would do so.