Key West is an island and city in the Straits of Florida on the North American continent. The city lies at the southernmost end of U.S. Route 1, the longest north-south road in the United States. Key West is the southernmost city in the contiguous United States and the westernmost island connected by highway in the Florida Keys. The island is about 4 miles (6.4 km) long and 1 mile (1.6 km) wide, with a total land mass of 4.2 square miles (11 km2). Duval Street, its main street, is 1.1 miles (1.8 km) in length in its 14-block-long crossing from the Gulf of Mexico to the Straits of Florida and the Atlantic Ocean. Key West is about 95 miles (153 km) north of Cuba at their closest points.

The city is the county seat of Monroe County. The city boundaries include the island of Key West and all or part of several nearby islands: Sigsbee Park, Fleming Key, Sunset Key, and the northern part of Stock Island. The total land area of the city is 5.6 square miles (14.5 km2). Key West is the southern terminus of U.S. Route 1, State Road A1A, the East Coast Greenway and, before 1935, the Florida East Coast Railway.

Key West is 129 miles (208 km) southwest of Miami by air, about 160 miles (260 km) by car, and 106 miles (171 km) north-northeast of Havana. Key West is a port of call for many passenger cruise ships. The Key West International Airport provides airline service. Naval Air Station Key West is an important year round training site for naval aviation due to the tropical weather, which is also the reason Key West was chosen as the Winter White House of President Harry S. Truman. The central business district is located along Duval Street and includes much of the northwestern corner of the island. The official city motto is "One Human Family."

Lisbon is the capital and the largest city of Portugal, with an estimated population of 505,526 within its administrative limits in an area of 100.05 km2. Its urban area extends beyond the city's administrative limits with a population of around 2.8 million people, being the 11th-most populous urban area in the European Union. About 3 million people live in the Lisbon Metropolitan Area (which represents approximately 27% of the country's population). It is mainland Europe's westernmost capital city and the only one along the Atlantic coast. Lisbon lies in the western Iberian Peninsula on the Atlantic Ocean and the River Tagus. The westernmost areas of its metro area form the westernmost point of Continental Europe, which is known as Cabo da Roca, located in the Sintra Mountains.