Exhibit 16.1 Ernst & Young, LLP 2901 Douglas Blvd., Suite 300 Roseville, CA 95661 March 22, 2005 Securities and Exchange Commission 450 Fifth Street, N.W. Washington, D.C. 20549 Gentlemen: We have read item 4.01 of Form 8-K filed March 22, 2005, of Waste Connections, Inc. and are in agreement with the statements contained in the first, second and third paragraphs on page 2 therein. We have no basis to agree or disagree with the other statements of the registrant contained therein. Very truly yours, /s/ Ernst & Young LLP