Avachinsky is an active stratovolcano in Russia. It is situated on the Kamchatka Peninsula in the Russian Far East. Avachinsky lies within sight of Petropavlovsk-Kamchatsky, the capital of Kamchatka Krai. Together with neighbouring Koryaksky volcano, it is considered a Decade Volcano, worthy of particular study in light of its history of explosive eruptions and proximity to populated areas.

The Kamchatka Peninsula is a 1,250-kilometre-long (777 mi) peninsula in the Russian Far East, with an area of about 270,000 km2 (100,000 sq mi). The Pacific Ocean and the Sea of Okhotsk make up the peninsula's eastern and western coastlines, respectively. Immediately offshore along the Pacific coast of the peninsula runs the 10,500-metre-deep (34,449 ft) Kuril–Kamchatka Trench.