The list of ship decommissionings in 1870 includes a chronological list of all ships decommissioned in 1870.
| Date | Operator | Ship | Pennant | Class and type | Fate and other notes |
|---|---|---|---|---|---|
| December 31 |  United States Navy | Saugus | Canonicus-class monitor | Laid up at Key West and towed to Philadelphia Navy Yard until recommissioned in 1872 [1] |
Ship commissioning is the act or ceremony of placing a ship in active service and may be regarded as a particular application of the general concepts and practices of project commissioning. The term is most commonly applied to placing a warship in active duty with its country's military forces. The ceremonies involved are often rooted in centuries-old naval tradition.
The first USS Pensacola was a screw steamer that served in the United States Navy during the U.S. Civil War.
The Miantonomoh class consisted of four monitors built for the Union Navy during the U.S. Civil War, but only one ship was completed early enough to participate in the war. They were broken up in 1874–1875.
The USS Piscataqua, a screw steamer, was launched 11 June 1866 by Portsmouth Navy Yard; and commissioned 21 October 1867 with Captain Daniel Ammen in command.
| Ship events in 1870 | |||||||||||
| Ship launches: | 1865 | 1866 | 1867 | 1868 | 1869 | 1870 | 1871 | 1872 | 1873 | 1874 | 1875 |
| Ship commissionings: | 1865 | 1866 | 1867 | 1868 | 1869 | 1870 | 1871 | 1872 | 1873 | 1874 | 1875 |
| Ship decommissionings: | 1865 | 1866 | 1867 | 1868 | 1869 | 1870 | 1871 | 1872 | 1873 | 1874 | 1875 |
| Shipwrecks: | 1865 | 1866 | 1867 | 1868 | 1869 | 1870 | 1871 | 1872 | 1873 | 1874 | 1875 |