Several proposed locations do not, by themselves, resolve TN eligibility. The assessment must identify the employer arrangement and qualifying professional work across those sites. Do not assume that one support letter covers work for every entity associated with the itinerary, especially when client companies or separately incorporated affiliates are involved.
Test what changes between sites
For a hypothetical offer covering a head office and a branch, compare the services, supervision, and legal employer at both. If the underlying job remains the same, the evidence should make that clear. If a second site introduces a different role or employment relationship, obtain advice about the authorization needed before accepting that assignment.
Geography is a useful organizing fact, but the professional category, credentials, citizenship, and temporary purpose still require their own evidence. Take the comparison in a set order rather than all at once. Begin with the legal employer at each site, because that answer determines whether one arrangement or several are in issue.
Move second to supervision, identifying the person who assigns and directs the work at each location. Third, compare the duties themselves against the listed profession, since a site that introduces sales or general operational management raises a different question from one that simply repeats the same professional work elsewhere. Hypothetical example: a soil scientist engaged by a U.S.
laboratory attends grower properties to take samples and returns to the laboratory to analyse them. Sampling and analysis are both professional work of the listed category, and one employer directs both. Had the grower separately engaged the same person to manage its operations, that second relationship would need its own assessment before any such work began.