So just to clarify — you do not need a visa to travel to Hong Kong or Macau. But you will need a Chinese visa if you are planning on crossing the border to check out Shenzhen or Guangzhou (or Beijing or Shanghai, etc.) in China.

This page from the Chinese embassy should give you all the details. The Q1 Tourist application form can be downloaded in pdf format here. It’s basically $130 for the visa, and allows for multiple entries.

It’s especially easy if you’re in NYC, DC, SF, LA, Chicago or Houston, all of which have consulates. We did a walk-in at the consulate on 42nd Street a few years ago and received the visa within a week, and bypassed any related passport-in-the-mail anxiety.