Having no other means of obtaining funds with which to equip an expedition, La Salle sold his seigneury and at once began his preparations. In July, 1669, he set off with a party of about twenty men, some of whom were missionaries sent by the Seminary of St. Sulpice to carry the tidings of the faith into the heart of the continent. Up the St. Lawrence and along the south shore of Lake Ontario they went, halting at Irondequoit Bay while La Salle and a few of his followers went overland to the Seneca villages in search of guides. Continuing to Niagara, the party divided and the Sulpicians made their way to the Sault Ste. Marie, while La Salle with the remainder of the expedition struck out south of Lake Erie and in all probability reached the Ohio by descending one of its branches. But, as no journal or contemporary record of the venture after they had left Niagara has come down to us, the details of the journey are unknown. It is believed that desertions among his followers prevented further progress and that, in the winter of 1669-1670, La Salle retraced his steps to the lakes. In its main object the expedition had been a failure.
Having exhausted his funds, La Salle had no opportunity, for the present at least, of making another trial. He accordingly asked Frontenac for trading privileges at Cataraqui, the site of modern Kingston, where stood the fortified post named after the governor. Upon Frontenac’s recommendation La Salle received in 1674 not only the exclusive right to trade but also a grant of land at Fort Frontenac on condition that he would rebuild the defenses with stone and supply a garrison. The conditions being acceptable, the explorer hastened to his new post and was soon engaged in the fur trade upon a considerable scale. La Salle, however, needed more capital than he himself could supply, and in 1677 he made a second trip to France with letters from Frontenac to the King and Colbert. He also had the further design in view of obtaining authority and funds for another trip of exploration to the West. Since his previous expedition in 1669 two of his compatriots, Pere Marquette and Louis Joliet, had reached the Great River and had found every reason for believing that its course ran south to the Gulf of Mexico, and not southwestward to the Gulf of California, as had previously been supposed. But they had not followed the Mississippi to its outlet, and this was what La Salle was now determined to do.