When did the Ohio Valley become safer for British settlers?

After the French told Pontiac about the Treaty of Paris

Explanation:

During the years of revolutionary war Ohio Valley become a middle region that separate the British and the Americans.

Before the creation of Treaty of Paris, every British Settlers who dare to cross this region will be treated with attacks or hostilities.

Treaty of Paris marked the end of the revolutionary war, and both Americans and the British agreed that the northern part of the Valley can be used by British Settlers. In the following years, this limitation become more lax and both sides eventually let each sides crossed lines.

But the treaty of pairs is definitely the one that become the make it possible for the British settlers to set foot on that region.