|National Expressway 1|
|West end:||4th Ring Road, Chaoyang, Beijing|
| G25 in Fengrun, Hebei |
G16 in Jinzhou, Liaoning
|East end:||Shuto Expressway Route 3, Setagaya, Tokyo|
National Expressway 1 (expressway designation NEX-1, part of the Asian Highway Network AH1) is the most heavily traveled designated National Expressway in the East Asian Federation. It is one of the most important links in the national transport network, currently connecting four of the five regional capitals, only missing Taipei. It serves some of the most heavily populated urban areas in the country, including Beijing, Shenyang, Sinuiju, Seogyeong, Seoul, Daejeon, Daegu, Busan, Fukuoka, Kitakyushu, Osaka, Kyoto, Nagoya, and Tokyo. It is by far the longest highway in the proposed National Expressway network, and will be more so when completed its full proposed length to Waruimizu, Karafuto by 2020. Most of the expressway predates the founding of the Federation, with the oldest section, a part of the Meishin Expressway from Osaka to Kyoto opening on July 16, 1963. Like most highways in East Asia, the entire expressway is tolled, but is operated by the National Expressway Corporation, majority-owned by the State Transport Office.
It is the longest of the expressways in the proposed National Expressway System, and, as currently designated, passes through 33 prefectures. It is the only National Expressway in the system currently signed as such. In expressway planning in the 1990s, before the advent of the Japan-Korea Undersea Tunnel, the corridor in Korea was designated NEX-1W, to be distinguished from the Japanese portion of the route, NEX-1E; the two would be connected by ferry service at Busan and Fukuoka. The opening of the Tunnel in 2010 has obviated the need for a distinction, and the two routes and the additional section in China now constitute NEX-1.
The NEX-1 mainly runs concurrent with existing expressways for its entire length. The western terminus of NEX-1, and its concurrency with the Beijing-Harbin Expressway (China Expressway G1) is at the Sifang Bridge, the interchange with Beijing's Fourth Ring Road. The expressway heads east from Beijing to Qinhuangdao, where it turns northeast to follow along the coast of the Bohai Sea. It follows the coastline for the remainder of the trip in Hebei Prefecture, crossing into Liaoning Prefecture. South of Jinzhou, it turns for a more inland route, towards Shenyang. Around Shenyang, the expressway splits with China Expressway G1, follows the southern side of the Shenyang Ring Expressway (China Expressway G1501), and merges with the Danfu Expressway (China Expressway G1113), proceeding south to Dandong. In Dandong, the expressway splits from China Expressway G1113 and proceeds onto an exclusive viaduct from there to the Yalu River, where it crosses the Yalu River Crossing into North Korea.
For its length in North and South Korea, NEX-1 follows the Singyeong Expressway, a pre-Federation expressway built by the Republic of Korea in the mid-1960s, connecting Sinuiju with Seoul. After the Yalu River Crossing, the expressway passes through downtown Sinuiju on an elevated viaduct over city streets. This method was chosen during the upgrades of the NEX route to minimize the disturbances to the existing city, and to prevent intermixing of local traffic with expressway traffic. After leaving the city to the south, the route follows the Yellow Sea through North Pyongan Prefecture. About 40 kilometers south of the junction with Korea Expressway N15, NEX-1 crosses into South Pyongan Prefecture, and the Seogyeong National Capital Region. In central Seogyeong, the NEX-1 is buried, with only seven interchanges inside of the city proper.
Leaving Seogyeong to the southeast, the route proceeds through the suburban countryside to the Kaesong Industrial Region, and proceeds into South Korea.