Alexyevskaya (often referred to as Alexyev or Sigma Indus α) was a UNSC-controlled outpost colony located in the Sigma Indus system of the second rim. Since the mid-2550s, Alexyevskaya has been the site of a plethora of UNSC Defense Force surface installations and a hefty naval resupply checkpoint; as such, it boasts a modest semi-permanent orbital fleet. It is also home to the operational command unit of the notable Advanced Warfare Fleet.