As of now, Denver, Colorado does not have any large virtual currency exchanges based in the city. However, there are several popular virtual currency exchanges that cater to customers in the United States as a whole, including those living in Denver.

Some of the largest virtual currency exchanges in the US include Coinbase, Kraken, Binance.US, Gemini, and Bitstamp. These exchanges allow users to buy, sell, and trade a variety of cryptocurrencies such as Bitcoin, Ethereum, and Litecoin.

Coinbase is one of the most well-known and widely used virtual currency exchanges in the US. It offers a user-friendly platform for buying and selling cryptocurrencies and has a large customer base. Kraken is another popular exchange that offers advanced trading features and a wide range of cryptocurrencies to choose from.

Binance.US is the American arm of the larger Binance exchange, which is one of the largest virtual currency exchanges in the world. Gemini is a regulated exchange founded by the Winklevoss twins that is known for its security features. Bitstamp is one of the longest-standing virtual currency exchanges, having been founded in 2011.

While Denver may not have any virtual currency exchanges based in the city, residents can easily access these popular exchanges online and start trading cryptocurrencies. It is important to do thorough research and choose a reputable exchange that offers the features and security measures that best suit your needs.