Troitsk is a former city, now a village in Kovylkino district of Mordovia, a Republic of Russia. It was founded in 1570.

• 77th Reserve Division (German Empire)
• 77th Street (BMT Fourth Avenue Line)
• 77th Street (BMT Fourth Avenue Line station)
• 77th Street (IRT Lexington Avenue Line station)
• 77th Street-Lenox Hill Hospital (IRT Lexington Avenue Line)
• 77th (The East Middlesex) Regiment of Foot
• 77th Training Reserve Battalion
• 77th West Virginia Senate
• 77 West Wacker Drive
• 7.7 x 58
• 7.7 x 58 Arisaka
• 7.7×58mm Arisaka
• 7800
• 7800gt
• 7800GT
• 7800GTX
• 7800°Fahrenheit
• 7-8-03 - New York, New York
• 7/8/03 – New York, New York
• 7805 (integrated circuit)
• 780 Armenia
• 780 BCE
• 780 in poetry
• 780 (New Jersey bus)
• 780th Aircraft Control and Warning Squadron