| Reinhard I, Lord of Hanau | |
| Noble Family: | House of Hanau |
| Father: | Reinhard II of Dorfelden |
| Spouse: | Adelaide of Münzenberg |
| Burial Place: | Arnsburg Abbey |
Reinhard I, Lord of Hanau ( - 20 September 1281; first mentioned in 1243) is the ancestor of the House of Hanau.
With Reinhard I the closed genealogy of the Lords and Counts of Hanau begins. He belongs to a family that was initially named after their ancestral Dorfelden Castle. They were first mentioned in a document in 1166/1168. From 1191, the family styled itself "Lords of Hanau". Their relationship, if any, with the earlier Lords of Buchen or the Lords of Dorfelden who ruled in the Hanau area before 1166, is not entirely clear.
Reinhard I was probably the son of Reinhard II of Dorfelden. Around 1243, he succeeded his uncle Henry II of Dorfelden as Lord, and reunited the possessions of his family in a single hand.
In 1260 Reinhard I accompanied his cousin Werner of Eppstein to Rome ("defying great hardships and dangers"), where Werner was consecrated as Prince-Archbishop of Mainz. As a reward, he received the post of Burgmann of Aschaffenburg, which was a completed fief after the death of Cornrad of Dornburg.
| thumb|75px|Coat of arms of the Counts of Rieneck in 1450-1480, according to Scheibler's Armorial | thumb|75px|Coat of arms of the Lords and Counts of Hanau, according to Scheibler's Armorial |
In 1266, Reinhard I reached an agreement with the city of Frankfurt, in which he and his heirs would receive a very high monetary compensation, if one of their subjects were to become a citizen of Frankfurt. This suggests, he was struggling with large numbers of subjects migrating to Frankfurt.
Reinhard I was from 1275 to 1279 Imperial Landvogt in the Wetterau area, and Burgrave of Friedberg. He was also Burgmann of the Kaiserpfalz Gelnhausen and of Rödelheim.
During his reign, Reinhard I managed to extend his territory. In 1255, his brother-in-law Ulrich II, Lord of Münzenberg died without a male heir. Reinhard's wife, Adelaide inherited a share of 1/6 of the Münzenberg Inheritance. In 1277, he inherited the district of Schwarzenfels from the Rieneck inheritance. He rounded off his territory by exchanging the manors in Benstadt, Stierstadt and Ossenheim with the Mariengreden chapter in Mainz for the forests of Hanau and Bulau.
He died on 20 September 1281 and was buried in Arnsburg Abbey.
In 1245, he married Adelaide, a daughter of Ulrich I of Münzenberg. As her dowry, she brought the district of Babenhausen into the marriage. They had four children: