Arlington County Public Schools is planning to build two new elementary schools — the first new schools since the 1990s — to handle the booming enrollment that’s straining the small district.

Superintendent Pat Murphy also is proposing several projects to add space in existing schools in her $537.7 million, 10-year Capital Improvement Plan. While past plans have focused on the upkeep of aging buildings, school officials say this is the first plan to build capacity that Arlington has ever put forth.