九十九里浜
Isumi is located on the east coast of southern Chiba Prefecture, on the Bōsō Peninsula. It is bordered by the Pacific Ocean to the east, and enjoys a temperate maritime climate, with short, cool winters and hot, humid summers due to the effects of the Kuroshio Current offshore. The area is noted for its beach resorts, which are at the end of the Kujūkuri Beach area, and the landscape consists of rolling, sandy hills. The Isumi River, a small river which runs through this portion of the peninsula, empties into the Pacific Ocean at Misaki. Parts of the city are within the Minami Bōsō Quasi-National Park. Mount Arakine is the highest point in the city, with an elevation of 157.8 meters. The city is approximately 45 kilometers from the prefectural capital of Chiba and 70 to 80 kilometers from central Tokyo.