Sacred Heart Prep junior Bradley Knox also had a good effort as he toured the picturesque flat layout in Carmel Valley with a 1-over 72.
Under normal circumstances, both scores would have been good enough to win league or section titles. Wednesday's tournament, however, was the CIF/CGA Boys Golf Championships -- also known as the state championships.
The scores by Buchanan and Knox were good, but not good enough to bring home individual honors on the short course that played 6,449 yards and featured 10 man-made lakes.
Top honors went to Jack Chung of Sunny Hills in Southern California. He shot a 5-under 66 to become the 2013 state champion. Miguel Delgado of Branson (Marin County) was runner-up with a 68 to earn top honors from Northern California.
Buchanan, in his first state tourney, was one of four golfers at 71 while tying for eighth. Knox, also in his first state finals, was in a group of five at 72, tying for 12th. The top finisher from the Central Coast Section was Seb Crampton of R.L. Stevenson with a 1-under 70. He helped his team win the state title with a 368 total. Sunny Hills was second at 370.
Crampton was the only CCS golfer ahead of Buchanan while Knox had only three ahead of him.
Buchanan, who has a scholarship to Southern Methodist University in the fall, capped his prep career with four birdies, 10 pars and four bogeys.
Starting on the 10th hole, Buchanan had four straight pars before getting a birdie on the 502-yard par-5 14th. He gave it right back with a bogey on the 15th, a 519-yard par-5. He picked up another birdie on the 146-yard par-3 17th to finish his first nine at 1-under.
A birdie on the 540-yard par-5 first hole put Buchanan at 2-under. He stayed that way until a bogey on the fourth hole, a 403-yard par 4. He gave back strokes on the sixth and seventh holes, both par-4s, before getting back to even with a birdie on the 541-yard par-5 ninth.
"It was a nice finish to my high school golf career and it felt good to birdie the par-5 ninth hole, which was my last hole today," Buchanan said. "It is definitely bittersweet to be leaving Menlo. I have really enjoyed my teammates and I am looking forward to playing for SMU in the fall."
Buchanan next will play in the 102nd California State Amateur on June 15 at Monterey Peninsula Country Club in Pebble Beach.
Knox also started on 10, just two groups ahead of Buchanan. He finished with six birdies, six pars, five bogeys and a damaging double-bogey six on the 408-yard par-4 16th that put him at 3-over for his first nine holes.
A bogey on the first hole put him at 4-over before Knox rallied with birdies on three straight holes to get to 1-over. A bogey on No. 6, a 349-yard par-4 was followed with a birdie on No. 8, a 216-yard par-3. Knox finished with a 2-under 33 on his second nine.