Monaco (ˈmɒnəkoʊ; mɔnako), officially the Principality of Monaco, is a sovereign city-state and microstate on the French Riviera a few kilometres west of the Italian region of Liguria, in Western Europe, on the Mediterranean Sea. It is bordered by France to the north, east and west. The principality is home to 38,682 residents, of whom 9,486 are Monégasque nationals; it is widely recognised as one of the most expensive and wealthiest places in the world. The official language of the principality is French. In addition, Monégasque (a dialect of Ligurian), English and Italian are spoken and understood by many residents.
With an area of , it is the second-smallest sovereign state in the world, after Vatican City. Its make it the most densely-populated sovereign state in the world. Monaco has a land border of and the world's shortest coastline of approximately ; it has a width that varies between . The highest point in the state is a narrow pathway named Chemin des Révoires on the slopes of Mont Agel, in the Les Révoires ward, which is above sea level. The principality is about from the border with Italy. Since 2013, it consists of nine administrative wards, the largest of which is Monte Carlo (Monte Carlo/Spélugues, ), and the most populous of which is Larvotto (Larvotto/Bas Moulins, 5,443 residents as of 2008). Through ongoing land reclamation, started in 1861 and accelerating in the 1960s, Monaco's small land mass has expanded by 20 per cent.
The principality is governed under a form of constitutional monarchy, with Prince Albert II as head of state, who wields immense political power despite his constitutional status. The prime minister, who is the head of government, can be either a Monégasque or a French citizen; the monarch consults with the Government of France before an appointment. Key members of the judiciary in Monaco are detached French magistrates. The House of Grimaldi has ruled Monaco, with brief interruptions, since 1297. The state's sovereignty was officially recognised by the Franco-Monégasque Treaty of 1861, with Monaco becoming a full United Nations voting member in 1993.