| Count Baltzar von Platen | |
| Birth Date: | 29 May 1766 |
| Birth Place: | Rügen, Swedish Pomerania |
| Death Place: | Christiania, Norway |
| Office: | Governor-general of Norway |
| Term Start: | 1827 |
| Term End: | 1829 |
| Predecessor: | Johan August Sandels |
| Successor: | Johan Caspar Herman Wedel-Jarlsberg |
| Occupation: | Naval officer, Architect |
| Spouse: | Hedvig Elisabeth Ekman |
Count Baltzar Bogislaus von Platen (29 May 1766 – 6 December 1829) was a Swedish naval officer and statesman. He was born on the island of Rügen, Swedish Pomerania (now in Germany), to Philip Julius Bernhard von Platen, Field Marshal and the Swedish Governor General of Pomerania, and Regina Juliana von Usedom.
At age 13 Baltzar entered the Royal Swedish Navy where he served with distinction until resigning in 1800, having attained the rank of captain.
Following the revolution in 1809 he became a member Government and, in the following year, received a promotion to rear admiral. He was also made chairman of the Göta Canal directorate charged with constructing a canal across Sweden. The canal, following a design by Thomas Telford, would only be completed in 1832, after von Platen's death, but during its construction, he did discover two skilled mechanical engineering brothers John Ericsson and Nils Ericson.
He was elected a member of the Royal Swedish Academy of Sciences in 1815. He was appointed Governor of Norway on 26 November 1827, a position which he held until his death in Christiania (modern name Oslo), the Norwegian capital, on 6 December 1829.
One of the early vessels built at Hammarsten shipyard in Norrköping was named after Baltzar von Platen in 1834.[1]
He was married to Hedvig Elisabeth Ekman. Baltzar von Platen's grave is at the side of the Göta Canal in Motala, where it is something of a tourist attraction, especially for canal visitors.