On Monday, Amazon (NASDAQ: AMZN) and electric vehicle maker Rivian (NASDAQ: RIVN) announced an expansion of their electric delivery partnership, bringing the service to over 100 U.S. cities ahead of the holidays. More than 1,000 custom Rivian EVs will be on the road delivering for Amazon in the coming months.

New cities added to the companies’ network include Austin, Texas; Boston; Denver; Houston; Indianapolis; Las Vegas; Madison, Wisconsin; Newark, New Jersey; New York; Oakland, California; Pittsburgh; Portland, Oregon; and Salt Lake City and Provo, Utah.

While still representing a small portion of Amazon’s fleet of 30,000 branded delivery vehicles and 20,000 branded trailers, custom EVs from Rivian are steadily weaving their way into the fabric of the company’s transportation network.