Yan'an (延安; Yánān) is a city in Shaanxi Province.
It is hard to believe that a city, so in the middle of nowhere, is considered a major pilgrimage site. Not a religious pilgrimage, but a pilgrimage site for those who follow the Communist philosophy. This is considered to be the "Cradle of Chinese Revolution"; it is where the Communists established their main base after the Long March. After Chairman Mao's birthplace in Shaoshan, is the number two pilgrimage site for those who are interested in recent Chinese history.
Yan'an is on one of the railway routes between Beijing and Xi'an. Several trains a day are available to Beijing West Railway Station (11 hrs), Taiyuan (5.5-6 hrs), Xi'an (3.5-4 hrs). There are also daily direct trains to Hohhot (9.5 hrs), Baotou (10 hrs), Chongqing (13 hrs), Chengdu (17 hrs), Shanghai (24 hrs). (Current schedule (in Chinese))
Tours from Xi'an that go to Hukou Waterfall will include this in the itinerary.
There is no high-speed train service (G- or D-series trains) to Yan'an. The closest cities with high-speed service are Xi'an and Taiyuan. Note that in Xi'an "regular" and high-speed trains use different stations, which means that transferring between a "regular" train from Yan'an and a high-speed train (e.g. to Guangzhou) would involve a fairly long subway ride.
In and around Yan'an there are several spots related to the history of the Chinese Communist Party. The place where Mao and his comrades lived and worked, places where party conferences were held and many more.
- Phoenix Hill (凤凰山). Lantau Peak is located in Yanan city centre, Yanan is one of the four famous mountains. Lantau Peak's highest elevation 1132 meters, mountain range rover, overlooking the breathtaking views of the Yanan.
- Yan'an Nursery. A communist play that is part of the 2-day tours from Xi'an. In Chinese: 延安保育院. Usually costs extra and a bit like an opera yet if you do not understand Chinese you can forget about enjoying it. ¥150.
- Zaoyuan 枣园. "Date Park" is a small public park that has the old housing of the Communist leaders. The part itself has not much to see but many souvenirs to buy. Free.
- Dog Head Dates. Called 狗头枣 as they are supposedly as big as a dog's head. These are healthy dates and one of the best places to buy them in China. You have to pay almost double in Beijing for example. People will let you try them from plates but be aware that this often means you are then led to a place to buy some. Better to just avoid the sellers unless you are prepared to buy from them.
Yan'an is not a usual destination for foreign visitors, so some communication skills will be needed to find a place in a local budget hotel. One option is to take the local bus from the train station to the town center, and get off in the center, in the stop just beneath a obvious triple-pedestrian-bridge. A local guest house (40-70Y per night per room) can be found just in front of the bus stop, on the second floor.