Grand Duchess Catherine Mikhailovna of Russia (Ekaterina Mikhailovna) was the third of five daughters of Grand Duke Michael Pavlovich of Russia (youngest son of Paul I of Russia) and Princess Charlotte of Württemberg.
On 6 February 1851 in St. Petersburg, Catherine married Duke Georg August of Mecklenburg-Strelitz (1824-76), second son of Georg, Grand Duke of Mecklenburg-Strelitz (1779–1860) and Princess Marie of Hesse-Kassel (1796–1880). They had four children:
1-Nikolaus (11 July 1854)
2-Helene (16 January 1857 – 28 August 1936); married Prince Albert of Saxe-Altenburg; they had no children.
3-Georg Alexander (6 June 1859 – 5 December 1909); married (morganatically) Natalia Vanljarskaya. Father of Duke Georg of Mecklenburg, Count of Carlow and great-grandfather of Duke Georg Borwin of Mecklenburg, current head of the House of Mecklenburg-Strelitz.
4-Karl Michael (17 June 1863 – 6 December 1934); renounced his succession rights in 1918