Daniel McLachlin was a businessman and political figure in Canada West. He represented Renfrew South in the 1st Canadian Parliament as a Liberal from 1867 to 1869.
He was born in Pointe-Fortune in Lower Canada in 1810 and had entered the timber trade in the Ottawa Valley by 1834. In 1837, he moved to Bytown and purchased cutting rights along the Ottawa River, Madawaska River and Indian Rivers. He built sawmills and gristmills at the Chaudière Falls on the Ottawa. He also operated a general store in Bytown with his brother Hugh until 1855. In 1851, he relocated his timber business to Arnprior, using the power of the Madawaska River to operate his mills. He also helped promote the development of the settlement there. The same year, he was elected to the Legislative Assembly for Bytown; he did not run in 1854 but was elected in 1861 for Renfrew. In 1867, he was elected by acclamation to the 1st Canadian Parliament for Renfrew South. He resigned from politics and his business in 1869, leaving the business to his sons. He died in Arnprior in 1872.