Beihai Park is located in the center of Beijing, occupying an area of 682,000 sq. meters. Its address is 1 Wenjin Street, Xicheng District, Beijing. The postcode is 100009.
To its southeast corner is the Forbidden City. In fact, its south gate is right across the street from the turret of the City. If you are pretty fit and active, you can put these two places on the same day in your itinerary to gain a comprehensive idea about how the emperors of ancient China worked and relaxed.
To its east is Jingshan Park, another historical and well-known park in China. You can climb the hill there and overlook the Forbidden City. To its south is the Middle Sea (Zhonghai) and South Sea (Nanhai), the workplace of the national leaders, the actual political center of China, just like the No. 10 on Downing Street. And of course, you are prohibited from entering these places.
There is nothing special to the west of Beihai Park, just some residential areas. But to its north is the Back Sea (Houhai), which is famous for two things: historical celebrities’ residences and numerous bars. You can have some drinks, feel the breeze, listen to popular Chinese songs, and take a good rest after walking for a whole day. There are also many Beijing snacks sold there, which I highly recommend you give a go.
Hundreds of bus routes pass through the north gate and the south gate of Beihai Park. But if you prefer the subway, you can take line 6, get off at Beihai Bei station (North of Beihai), and walk east for about 100 meters to get to its north gate.