Once tens of thousands of trees (mostly planted in the 1960s) were removed between the early 90s and 2015, Oakmont’s original penal design was re-established, with the game’s nastiest, most notorious bunkers (founder-architect H.C. Fownes staked out bunkers whenever and where ever he saw a player hit an offline shot), deep drainage ditches and ankle-deep rough. Oakmont also has the game’s swiftest putting surfaces, which were showcased during the U.S. Open in 2016, despite early rains that slowed them down a bit. Gil Hanse and Jim Wagner made bunker modifications and expanded the greens throughout the course in 2023 in preparation for the 2025 U.S. Open. The USGA has already awarded Oakmont three additional Opens between 2033 and 2049, reinforcing its title as it the Host of the Most U.S. Opens ever.
— Derek Duncan and Stephen Hennessey, Golf Digest.