State Route 236 (SR 236) is a state highway located in extreme southern Maine, entirely within York County. It begins at State Route 103 in Kittery and runs 15.72 miles (25.30 km) north, terminating at State Route 9 in Berwick. Between Kittery and South Berwick, SR 236 is known as the Harold L. Dow Highway. The highway runs roughly parallel to the New Hampshire border (the Salmon Falls River) over its entire length.

The southern terminus of SR 236 is at the intersection of SR 103 (Whipple Road), Woodlawn Avenue, and Shapleigh Road in Kittery, near the Portsmouth Naval Shipyard. It follows Shapleigh Road and Rogers Road to the Kittery Traffic Circle, where it connects to US 1, US 1 Bypass, and Old Post Road. The rotary marks the southern end of the Dow Highway. SR 236 has partial interchanges with US 1 Bypass and I-95, then continues northwest along the former right-of-way of the B&M Railroad until intersecting SR 4 in South Berwick at the northern end of the Dow Highway. SR 236 is cosigned with SR 4 in downtown South Berwick, then splits off to follow Berwick Road into downtown Berwick along Allen Street to its northern terminus at SR 9 (School Street), approximately 1,200 feet (370 m) east of the New Hampshire state line. To the west, SR 9 crosses the Salmon Falls River into Somersworth, New Hampshire and continues west as NH 9 / NH 236.

NH 236 (which terminates at the state border) is a westward extension of SR 236 through downtown Somersworth to NH 108 south of Rochester. Though it does not directly connect to SR 236 as signed, the two routes are connected by SR 9.

The northern section of SR 236, from Gould's Corner (near SR 103 and SR 101) in Eliot to downtown Berwick, was originally designated in 1929 as part of SR 103. That route was truncated to its current terminus in 1957, and its northern segment was re-designated as SR 236. Both SR 103 and SR 236 have a terminus at the other route. Most of the southern part of SR 236 between I-95 in Kittery and SR 91 in South Berwick was built in 1956 on the former right-of-way of the B&M Railroad after service was discontinued and the tracks removed four years earlier. While railroad service has disappeared, SR 236 is a busy commuter corridor connecting to I-95, the Portsmouth Naval Shipyard, and downtown Portsmouth.

The entire route is in York County.

Location	mi	km	Destinations	Notes
Kittery	0.00	0.00	SR 103 (Whipple Road) – Eliot, York	Southern terminus
	0.98– 1.08	1.58– 1.74	US 1 (State Road) to I-95 north – York, Portsmouth NH	Rotary
	1.14– 1.27	1.83– 2.04	US 1 Byp. south – Portsmouth NH	Partial interchange; no access to US 1 Bypass north from SR 236; access from US 1 Bypass north via Kittery Circle
	1.27– 1.49	2.04– 2.40	I-95 south – Portsmouth NH, Boston MA	Exits 2 & 3 on I-95 No access to I-95 north from SR 236; access via US 1 north
Eliot	7.05	11.35	SR 103 east (State Road) – Eliot	Western terminus of SR 103
	7.44	11.97	SR 101 (Dover Road / Goodwin Road) – Kittery, Dover NH
South Berwick	10.14	16.32	SR 91 south (York Woods Road) – York	Northern terminus of SR 91
	10.40– 10.43	16.74– 16.79	Great Works River
	11.84	19.05	SR 4 south (Main Street) – Rollinsford NH, Dover NH	Southern terminus of SR 4 concurrency
	12.04	19.38	SR 4 north (Portland Street) – North Berwick, Sanford	Northern terminus of SR 4 concurrency
Berwick	15.72	25.30	SR 9 (School Street) – North Berwick, Somersworth NH	Northern terminus
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Concurrency terminus       Incomplete access