Princess Louise Henriette Karoline of Hesse-Darmstadt (15 February 1761 – 24 October 1829), was the first Grand Duchess of Hesse and by Rhine by marriage.

Louise married on 19 February 1777 in Darmstadt, her cousin the then hereditary prince Louis I of Hesse-Darmstadt (1753–1830).

Her husband ruled Hesse-Darmstadt from 1790 as Landgrave Louis X and from 1806 as Ludwig I, Grand Duke of Hesse and the Rhine.

[1] Johann Wolfgang von Goethe stayed at her court and Friedrich Schiller read from his Don Carlos in her salon.

It was said that Napoleon Bonaparte promised the beautiful Louise, whom he believed to be one of the cleverest women of her time, that he would give her a crown.