Chaeng Watthana Road (Thai: ถนนแจ้งวัฒนะ) begins at Pak Kret in Nonthaburi Province, and leads eastward (and slightly south) to Lak Si Monument in Bangkok's Bang Khen District, where it crosses Phahon Yothin Road and from there becomes known as Ram Inthra Road (ถนนรามอินทรา, also spelled Ramindra) until it reaches Min Buri in Bangkok's eastern fringes.

It then leads north, crossing the Sankamphaeng Mountains through a pass between Khao Yai and Thap Lan national parks into Nakhon Ratchasima Province.

There, it passes through Wang Nam Khio and Pak Thong Chai districts before joining Mittraphap Road as it enters the city of Nakhon Ratchasima.

[3] The Kabin Buri–Nakhon Ratchasima section was built and paved from 1965 to 1968 with assistance from the United States Army to support the USAF bases in Thailand during the Vietnam War.

[4] The road, which cuts through the Dong Phayayen–Khao Yai Forest Complex World Heritage Site, underwent expansion into a four-lane highway from 2015 to 2018, which included the construction of bridges and underpasses to serve as wildlife corridors, the first in Thailand.