Cainta is bounded on the north by Marikina City and San Mateo, on the west by Pasig City, and on the east and south by Taytay. It lies in the Marikina Valley, is 10% rolling hills and 90% residential-industrial. It has the province's highest number of rivers and streams. Historians claim that Cainta's old geographical boundaries encompassed the mountain slopes of Montalban.