Where it sits
Phnom Penh is a municipality rather than an ordinary province, and it occupies the confluence the Khmer call the Chaktomuk — the four faces — where the Mekong meets the Tonlé Sap and splits again into the Bassac. That junction is why the city is here, and why the riverfront remains its social centre.
The capital was moved here from Oudong in 1866 under King Norodom, and the Royal Palace was laid out immediately afterwards. Much of what visitors walk through today — the palace compound, Wat Ounalom, the grid of the old French quarter — dates from that period or the decades of the protectorate that followed.
What to see
The essential sights cluster into a walkable riverside core: the Royal Palace and Silver Pagoda, the National Museum with the world’s finest collection of Khmer sculpture, and Wat Phnom on its small hill to the north.
Two sites deal with the Khmer Rouge period — Tuol Sleng, the school used as security prison S-21, and the Choeung Ek killing fields fifteen kilometres south. They are difficult and essential. Give them a morning between them and plan nothing demanding afterwards.
For markets, the art-deco dome of Psar Thmey and the cramped, excellent Tuol Tompoung — the Russian Market — pull in opposite directions and are both worth an hour.
Where to base yourself
BKK1 is the reliable first choice: embassies, quiet streets, good coffee, and the densest concentration of mid-range boutique hotels in the city. Daun Penh puts you within walking distance of the palace and the river. The riverside strip along Sisowath Quay is the most convenient and the noisiest.
Rates run noticeably below Siem Reap for equivalent quality, and the capital rarely sells out the way the temple town does in December.