Maen Si (Thai: แม้นศรี, pronounced [mɛ́ːn sǐː]) is an intersection of Bamrung Mueang, Worachak, and Chakkraphatdi Phong roads in area of Bangkok's Ban Bat sub-district, Pom Prap Sattru Phai district.
It's considered to be the intersection next to the Samran Rat (also known as Pratu Phi) on Bumrung Mueang road near the area of Wat Saket.
[1] Landmark of Maen Si intersection is Metropolitan Waterworks Authority (MWA)'s building site on Bamrung Mueang side.
It's the first headquarters of MWA build in 1914 during early the reign of King Vajiravudh (Rama VI) and the origin of water supply in Thailand.
Their ancestors evacuated the war from Dawei (formerly Tavoy) in Tanintharyi region to Rattanakosin (presently Bangkok) since the reign of King Phutthayotfa Chulalok (Rama I), there's evidence that "Trok Thawai" (ตรอกทวาย; Thawai is Tavoy in Thai) or officially known as Soi Maen Si 1 (ซอยแม้นศรี 1; Maen Si 1 alley).