Officially getting an international border in 1848, this area of land is up to 150 miles wide & has about 2,000 miles of coastline

In the November 3, 2025 episode of Jeopardy, the Final Jeopardy category was The Western Hemisphere, and the clue pointed contestants toward a distinctive stretch of land in North America. The clue read: “Officially getting an international border in 1848, this area of land is up to 150 miles wide & has about 2,000 miles of coastline.” This prompt referred to a historically significant region shaped by 19th-century treaties and known for its sweeping coastline along the Pacific. The answer drew on both geographic scale and the history of territorial agreements between the United States and Mexico.

What is the Baja California Peninsula?

The correct response was “What is Baja California?” This peninsula in northwestern Mexico stretches roughly 760 miles down the Pacific coast, with a width that varies widely, reaching up to around 150 miles at its broadest. Its combined Pacific and Gulf of California coastline approaches 2,000 miles. Baja California received its formal international border at the end of the Mexican-American War in 1848, when the Treaty of Guadalupe Hidalgo established the modern boundary between the United States and Mexico.

Historical Context and Border Formation

Baja California’s modern border was a direct result of one of the most consequential diplomatic agreements in North American history. The Treaty of Guadalupe Hidalgo concluded the Mexican-American War and determined the division of land between the two countries. While Mexico ceded a vast territory to the United States—including what would become California, Nevada, Utah, Arizona, New Mexico, and parts of Colorado and Wyoming—the Baja California peninsula remained part of Mexico. The treaty formally set the border at the Rio Grande in the east and at the line dividing Alta California (ceded to the U.S.) from Baja California (retained by Mexico) in the west.

The peninsula’s position made it strategically significant during negotiations. U.S. leaders considered acquiring it along with Alta California, but Mexico successfully maintained sovereignty over Baja California during the treaty discussions. The result cemented the peninsula as a Mexican territory with a newly defined international boundary, clarifying territorial limits amid a major shift in control of western North America.

Geographic Features and Coastline

Baja California’s geography stands out for both its length and its dramatic coastline. The nearly 2,000-mile shoreline is split between the Pacific Ocean on its western side and the Gulf of California—also known as the Sea of Cortez—on the east. This long coastal sweep shapes the region’s ecology, climate, and economic activities, including fishing, tourism, and marine conservation efforts. The peninsula’s width varies significantly, with the widest point stretching close to 150 miles.

The region is also known for its rugged terrain, featuring deserts, mountain ranges, and coastal plains. Natural attractions such as the Sierra de San Pedro Mártir mountains and the unique marine environments of the Gulf contribute to its environmental importance. The peninsula remains sparsely populated relative to its size, with urban centers concentrated near the U.S. border and along key coastal areas.

Modern Identity and Administrative Division

Today, Baja California is divided into two Mexican states: Baja California in the north, bordering the U.S. state of California, and Baja California Sur in the south. The northern state includes Tijuana, Mexicali, and Ensenada, while Baja California Sur includes La Paz and Cabo San Lucas. The border with the United States at Tijuana and Mexicali remains one of the busiest crossings in the Western Hemisphere, reflecting long-standing economic and cultural links between the regions.

Despite its official boundary being drawn in the mid-19th century, Baja California has developed its own distinct regional character over time. Its proximity to the United States has influenced both commerce and travel, while its remote southern stretches retain quieter coastal communities and natural reserves. The region’s identity blends its geographical isolation with its historical role in defining national boundaries in North America.

Significance in Jeopardy Context

The clue required contestants to connect historical events with geographical characteristics. Referencing 1848 immediately pointed to the Treaty of Guadalupe Hidalgo, while the specific measurements—up to 150 miles wide and about 2,000 miles of coastline—narrowed it to a coastal landform rather than a large inland border region. Baja California’s distinct size, shape, and treaty-based border made it the fitting and precise solution.

This Final Jeopardy example showcased the show’s classic intersection of history and geography, rewarding contestants who can connect territorial history with physical landscapes across the Western Hemisphere.