The 1910 U.S. Open was the sixteenth U.S. Open, held June 17–20 at Philadelphia Cricket Club in Chestnut Hill, Pennsylvania, a neighborhood of northwest Philadelphia. Alex Smith, the champion four years earlier, prevailed in an 18-hole playoff over his younger brother Macdonald Smith and 18-year-old John McDermott to win his second U.S. Open.

On Friday, Alex Smith opened with a pair of 73's to take the 36-hole lead by two shots ahead of McDermott, Gilbert Nicholls, Fred McLeod, and Tom Anderson.

Smith carded a 79 in the third round on Saturday morning that left him two behind McDermott, who shot a 75 for 223. In the final round that afternoon, McDermott was the first to finish and posted another 75 and a 298 total. Macdonald Smith shot 71 that also placed him at 298. McLeod had a chance to also post 298 after driving the final hole, but his putt for a two stayed out and he finished a shot back. Alex Smith also drove the green at the last needing only a two-putt to win, but he missed from 18 inches (45 cm) and tied with McDermott and his brother. Alex was not fazed by the near-miss; in the Monday playoff, his 71 beat McDermott by four and Macdonald by six.

McDermott won the next two U.S. Opens; he was the first American-born winner and remains the youngest champion (19) through 2016. Four-time champion Willie Anderson played in his final U.S. Open and finished eleventh; he died four months later of epilepsy at age 31.

The course also hosted in 1907 and is the present-day St. Martin's course, now nine holes.

Friday, June 17, 1910 (morning)

Place	Player	Score	To par
1	Tom Anderson	72	−1
T2	Tom McNamara	73	E
	Gilbert Nicholls
	Alex Smith
T5	Willie Anderson	74	+1
	John McDermott
	Macdonald Smith
	James R. Thomson
T9	Herbert Barker	75	+2
	George Low

Source:

Friday, June 17, 1910 (afternoon)

Place	Player	Score	To par
1	Alex Smith	73-73=146	E
T2	Tom Anderson	72-76=148	+2
	John McDermott	74-74=148
	Fred McLeod	78-70=148
	Gilbert Nicholls	73-75=148
T6	Jack Hobens	74-77=151	+5
	Tom McNamara	73-78=151
T8	Willie Anderson	74-78=152	+9
	George Low	75-77=152
	Macdonald Smith	74-78=152
	Chay Thom	80-72=152

Source:

Saturday, June 18, 1910 (morning)

Place	Player	Score	To par
1	John McDermott	74-74-75=223	+4
2	Tom McNamara	73-78-73=224	+5
T3	Jack Hobens	74-77-74=225	+6
	Gilbert Nicholls	73-75-77=225
	Alex Smith	73-73-79=225
6	Fred McLeod	78-70-78=226	+7
T7	Tom Bonnar	74-78-75=227	+8
	Macdonald Smith	74-78-75=227
T9	Willie Anderson	74-78-76=228	+9
	Jock Hutchison	77-76-75=228

Source:

Saturday, June 18, 1910 (afternoon)

Place	Player	Score	To par	Money ($)
T1	Alex Smith	73-73-79-73=298	+6	Playoff
	John McDermott	74-74-75-75=298
	Macdonald Smith	74-78-75-71=298
4	Fred McLeod	78-70-78-73=299	+7	80
T5	Tom McNamara	73-78-73-76=300	+8	65
	Gilbert Nicholls	73-75-77-75=300
7	Jack Hobens	74-77-74-76=301	+9	50
T8	Tom Anderson	72-76-81-73=302	+10	30
	Herbert Barker	75-78-77-72=302
	Jock Hutchison	77-76-75-74=302

Source:

Monday, June 20, 1910

Place	Player	Score	To par	Money ($)
1	Alex Smith	71	−2	300
2	John McDermott	75	+2	150
3	Macdonald Smith	77	+4	100

Source:

• 1910 U.S. Open
• USGA Championship Database

40°03′54″N 75°12′32″W / 40.065°N 75.209°W / 40.065; -75.209