7 July] 1877 – 2 September 1962) was a Russian military and political figure, and the first revolutionary commandant of Petrograd during the February Revolution.

From the autumn of 1916, representing the Zemstvo-Octobrist faction, he worked within the Progressive Bloc and was a supporter of the Ministry of Trust.

Engelhardt was a member of the executive committee of the Council of Officers' Deputies of the city of Petrograd, its environs, the Baltic Fleet and the Separate Border Guard Corps.

In November 1918 in Ukraine, from the autumn of 1918 he was the head of the political department of the Volunteer Army representative office in Kyiv, and from December 1918 in Odessa.

In the summer of 1919 at the headquarters of the troops of the Southwestern Territory (Odessa), from December 1919 he was the head of the same propaganda department.

Engelhardt lived in exile in France where he worked as a taxi driver, then in Latvia as a trainer at the Riga Hippodrome.

After the Baltic republics were annexed by the Soviet Union, Engelhardt was arrested and served administrative exile in the Khorazm Region from 1940 to 1946.

In 1946, he was allowed to return to Riga, where he worked as a translator from French, English, and German at the Hydrometeorological Service.