The mills he had founded at Waltham grew exceedingly prosperous under the management of Jackson; and it was not long before Jackson and his partners Appleton and Moody were seeking wider opportunities.

By 1820 they were looking for a suitable site on which to build new mills, and their attention was directed to the Pawtucket Falls, on the Merrimac River.

The land about this great water power was owned by the Pawtucket Canal Company, whose canal, built to improve the navigation of the Merrimac, was not paying satisfactory profits.

The partners proceeded to acquire the stock of this company and with it the land necessary for their purpose, and in December, 1821, they executed Articles of Association for the Merrimac Manufacturing Company, admitting some additional partners, among them Kirk Boott who was to act as resident agent and manager of the new enterprise, since Jackson could not leave his duties at Waltham.
The story of the enterprise thus begun forms one of the brightest pages in the industrial history of America; for these partners had the wisdom and foresight to make provision at the outset for the comfort and well-being of their operatives.

Their mill hands were to be chiefly girls drawn from the rural population of New England, strong and intelligent young women, of whom there were at that time great numbers seeking employment, since household manufactures had come to be largely superseded by factory goods.