Xuanquanzhi: How a Han Dynasty Relay Station on the Silk Road Ran China's First 'Post Office'
Sixty-four kilometers west of Dunhuang, in the flat Gobi, stands a rectangle of crumbling rammed-earth walls. To most travelers it looks like another nameless ruin. To historians it is China's most important ancient postal address: Xuanquanzhi (悬泉置), the only Silk Road relay station ever fully excavated, and the source of over 23,000 inscribed slips documenting how imperial China moved information, officials, and guests across 2,000 kilometers of desert.
The name means "Hanging Spring Station," from a spring that once trickled from the nearby mountains. For roughly two centuries — from about 111 BCE under Emperor Wu to 107 CE — the compound served as post office, guesthouse, and logistics depot, one link in a chain of over 80 stations between the Han capital Chang'an and the Silk Road frontier.
What the Excavators Found
Identified in 1987 and excavated from 1990 to 1992, the site proved to be a fortified compound covering 22,500 square meters — a walled enclosure (wu) about 48 meters square, with gate towers, stables, kitchens, offices, and dormitories around a courtyard. The dig was named one of China's top ten archaeological discoveries of 1991.
The real treasure was in the trash. Over 35,000 Han bamboo and wooden slips were recovered — more than 23,000 with writing — one of the largest caches of Han administrative documents ever found. The slips record mail deliveries, travel passes, grain accounts, and guest registers: the station's daily paperwork, preserved by the same dryness that saved the Dunhuang caves. The earliest dated slip is from 111 BCE, the latest from 107 CE.
Alongside the slips came other firsts: more than 460 pieces of hemp paper, over a dozen bearing legible ink writing, which rank among the earliest writing paper found anywhere in the world — pushing evidence for papermaking back nearly a century before the traditionally credited inventor Cai Lun. Archaeologists also found a silk letter, the longest and best-preserved private Han-era letter yet known, still readable today.
A Working Day at the Station
The slips let historians reconstruct daily operations. Staff fluctuated between about 30 and 50 people — officials, clerks, grooms, and soldiers — supported by roughly 40 horses and 6 to 15 carriages, with authority to requisition extra carts and animals from local farmers when envoys arrived in numbers.
The station ran a strict relay system. Official documents moved station to station at regulated speeds: urgent military intelligence could travel as fast as 400 li (about 165 kilometers) per day on horseback, with the mail bundled, sealed with clay impressions, and logged at every handover — a chain of custody the modern courier industry would recognize. Every pouch was tagged with its destination, routing, and classification.
The station doubled as a guesthouse for Silk Road traffic. Its registers record envoys, nobles, and merchants traveling between the Han court and Central Asian kingdoms, including parties from as far west as Parthia (modern Iran). The state fed and housed credentialed travelers, changed their horses, and moved them on — and when a mission from the kingdom of Kangju complained about its reception, both the complaint and the official response survived on slips. Guest feedback loops existed in 50 BCE.
From Relay Riders to the Modern Post Office
The relay system outlived the Han. The Tang re-opened the station as Xuanquan Post; the poet Jia Dao spent an uneasy night there on his way into exile. The station was finally abandoned in the Song dynasty, when its water source and its road both faded.
Its legacy is visible today in an unexpected place: the Chinese postal service. In 1982, to mark the founding congress of the All-China Philatelic Federation, China Post issued a miniature sheet featuring a painted brick from a Wei-Jin dynasty tomb near Jiayuguan: a galloping courier holding his credential aloft, his horse at full stretch. The image — the famous "Courier on Horseback" — later appeared on China Postal Savings Bank cards and became, in effect, the face of Chinese mail. The painting, the courier, and the postal tradition it celebrates all trace back to the world documented at Xuanquanzhi.
Visiting the Station Today
Since April 2025, the site has been open as part of the "Symphonic Silk Road Line 1" cultural tourism complex, built around the Liuge Expressway service area between Dunhuang and Guazhou. A full-scale reconstruction of the station's walled compound lets visitors walk through the post office, scribe's office, and meeting halls, furnished according to the archaeological record. The original slips and artifacts are displayed at the Gansu Jiandu (bamboo-slip) Museum in Lanzhou, and the Xuanquanzhi site — inscribed as part of the Silk Roads World Heritage listing in 2014 — remains a stop for travelers combining Dunhuang's Mogao Caves with the wider Hexi Corridor circuit.