The present site of the Phra Ratchawang Metropolitan Police Station and Museum Siam was once part of Wang Tai Wat Phra Chetuphon (royal residence behind Wat Pho), the fifth palace built during King Rama III’s reign. It was home to several royal family members and was eventually passed down to Prince Naruban Mukkamat, who lived there until his passing in 1896 (King Rama V’s reign). Afterward, the mansion grounds were repurposed.

During King Rama VI’s reign, the area was granted for government use, and in 1914, the police station was constructed in a Western architectural style. The original Phra Ratchawang Police Station, known as Thana Thewet or Tha Tian Police Station, was previously located across from the Reclining Buddha chapel at Wat Pho. That earlier station was a two-storey building resembling the Ministry of Defence.

The present building was constructed at the junction of Maharaj Road and Sanam Chai Road, historically called Sa Kak Wang (Three-way junction of the Palace) by the local Chinese community. The building was designed by Italian architect Mario Tamagno, who served under the Ministry of Public Works. Its establishment reflected Siam’s growing need to modernise its police system.

The station marked a turning point in Siam’s police reform, evolving from traditional pontrawen units into a centralised metropolitan force, following the modernisation policy of King Chulalongkorn (King Rama V) and shaped by figures such as Captain S.J. Ames and Arthur John Alexander Jardine. Designed in Western architecture, the building symbolised the modern identity of law enforcement and enabled the integration of multiple precincts into a more systematic form of public service. It stands as tangible evidence of Thailand’s transition to international standards in law, order, and urban governance.