Pathum Wan, Thailand

Sometime before 1855, Mongkut had part of the royal fields south of the canal landscaped with ponds and waterways, which were planted with decorative lotuses, for leisurely visits. A royal villa was built there, which was named Pathum Wan, meaning "lotus forest" (from Pali paduma + vana). A temple, named Wat Pathumwanaram, was also built next to the palace. The King made annual visits to the palace and the temple, at first travelling by boat. A road was later built, continuing eastward from Bamrung Mueang Road, linking the palace to the city. It was originally known as Sa Pathum or Pathum Wan Road before being renamed Rama I Road in 1920.

With the royal development, the area began to attract more residents, and more palaces were built during the following reign of King Chulalongkorn (Rama V, 1868–1910). The King had a palace built for Prince Svasti Sobhana west of Pathum Wan Palace in 1880, and commissioned Windsor Palace in 1881 for his own son Prince Vajirunhis, buying up large amounts of land for what was to be its extensive grounds. He also later gifted a plot of land to another son, Prince Mahidol Adulyadej, though it was Mahidol's mother Queen Savang Vadhana who oversaw the construction Sa Pathum Palace there after Chulalongkorn died in 1910.

Windsor Palace had become vacant following Vajirunhis's death in 1895, and its grounds became the site of several successive educational institutions which became established as Chulalongkorn University in 1917 by King Vajiravudh (Rama VI, r. 1910–1925). By then, several canals, roads and railways had been built through the area. West of the university grounds the Bangkok Railway Station, the country's main terminus, had been built in 1916. To the east, the Phloen Chit area was developed by the enterprising businessman Nai Lert around the same time. When the administration of Bangkok's districts was reorganized in 1915, the district was established as Amphoe Pathum Wan, bounded by Khlong Saen Saep to the north, the Chong Nonsi Railway to the east, Khlong Hua Lamphong to the south, and Khlong Phadung Krung Kasem to the west. Its status, along with Bangkok's other districts', was later changed from amphoe to khet in 1972.

Pathum Wan District saw increasing development throughout the 20th century, especially since the 1970s when the area along Rama I and Phloenchit roads became developed as a major shopping and commercial district. The Erawan Hotel opened on Ratchaprasong Intersection in 1956, and the Thai Daimaru department store, famous for introducing air conditioning and the escalator, opened on the opposite corner in 1964. Siam Square was developed as a low-rise retail area by Chulalongkorn University the same year, and the Siam Inter-Continental Hotel opened opposite it in 1966. Rajadamri Arcade—a modern, enclosed shopping mall—opened at Ratchaprasong in 1972, and Siam Center (next to the Inter-Continental) followed the next year. Gradually, Siam and Ratchaprasong supplanted the Wang Burapha area as Bangkok's centre of urban retail and youth culture. With the opening of the BTS Skytrain in 1999, the location of its central interchange at Siam station helped cement the neighbourhood's prominence as Bangkok's modern-day city centre. The area's prominence led to its occupation by anti-government protesters in 2010, which ended in a violent military crackdown.

The legal case about demolishing a high-rise on Soi Ruamrudee, was finally decided in 2025 by the Supreme Administrative Court; "The ruling means that no more legal barriers to demolition remain", according to media. The high-rise was built in 2005, without proper authority.