| Year |
Description |
| 1743 |
William Cromwell surveys the metes and bounds of a tract of land on the Patapsco for Caleb and Edward Dorsey |
| 1761 |
John Cornthwaite establishes Dismal Mill at present day Ilchester |
| 1762 |
Citizens of Elk Ridge Landing petition the Maryland Assembly for a town charter. Though unsuccessful, the petition makes an important and prescient point about change: "There is now a considerable Trade carried on (at the landing) and from its advantages situation would become a great Market for Grain if merchants could have any ground on any tolerable terms for building warehouses and other conveniences for carrying on trade there" |
| 1771 |
The Ellicott's purchase land in the Patapsco Valley |
| 1779 |
The earliest known drawing of Ellicott's Lower Mills is made by George Ellicott |
| 1806 |
Ellicott's found the Iron Rolling and Slitting Mill |
| 1807 |
The Baltimore and Fredericktown Turnpike Road, promoted by the Ellicott's, connects to the National Road John Hagerty is listed as owner of "one of the largest paper mills in the United States, 120 feet long by 40 wide, and three stories high, built of stone. |
| 1808 |
William Patterson and others established Union Manufacturing Company for producing textiles on the Patapsco. By 1825 the company will operate seventy six power looms and four thousand spindles. The company operated until 1887. |
| 1815 |
The Patapsco Cotton Factory is incorporated by the Maryland General Assembly. |
| 1824 |
The Thistle Mill, a textile manufactory, opens at Ilchester. |
| 1828 |
The Baltimore and Ohio Railroad raises a trestle across the river to Patapsco Mill. |
| 1837 |
The panic of 1837, tied to Andrew Jackson's attacks on the Bank of the United States, seriously affects the Ellicott Family's investments. |
| 1845 |
Fire destroys the Avalon Nail and Iron Works. |
| 1856 |
Orange Grove Flour Mill opens. |
| 1868 |
Great flood on the Patapsco devastates the towns and industry. |
