District 142A is bounded on the West by Darien and on the North by New Canaan and on the South by the Connecticut Turnpike (I-95). The Eastern border is more complicated. Starting at I-95, that border runs north on Scribner Avenue; east on Ledgebrook Drive and continuing east on Gillies Lane; then north on North Taylor Avenue all the way to Fillow Street; then east on Fillow past Kendall Elementary School, and east on Van Ness Street to Devon Avenue; south on Devon Avenue for one block to Girard Street and east on Girard Street and then Hill Street to Riverside Avenue, then northerly on Riverside Avenue to Ponus Avenue. From that point, the north-eastern border then follows Ponus Avenue to Spring Hill Avenue; turns south on Spring Hill Avenue to Ingleside Avenue, runs westerly along Ingleside Avenue to Beau Street, and northerly on Beau Street back to Ponus Avenue; the border then goes south, west and north around Ponus Ridge Middle school to Lancaster Drive and continues on Lancaster Drive back to Ponus Avenue, and then follows Ponus Avenue to the New Canaan border.

The major addition to the district is the Spring Hill area just north of Kendall School, which was added to replace the area south of I-95 which is now included in new District 142C and which votes at Brookside School.