My 1000x1000 blocks of roads:

"Clinched": MA 1A (northern segment), US 3 (Massachusetts only), MA 3A (northern segment), MA 4, MA 22, MA 35, MA 38, MA 40, MA 60, MA 97, MA 107, MA 108, MA 110, MA 113, MA 114, MA 125, MA 127, MA 127A, MA 129, MA 129A, MA 133, MA 145, MA 150, MA 286, MA 213

Partial: US 1, MA 2, MA 2A, MA 3, MA 9, MA 16, US 20, MA 27, MA 28, MA 30, MA 62, MA 70, MA 85, I-90, I-93, MA 111, MA 117, MA 119, MA 126, MA 128, MA 225, I-290, I-495