[2] The archipelago was formally incorporated as an administrative unit of China in 1281 under Tong'an County of Jiangzhe Province in the Yuan dynasty.

In the Song dynasty (960–1279), it was mentioned that in the Tang period, "Pinghu" barbarians from beyond Quanzhou had laid siege to Fuzhou, now the capital of Fujian Province.

[2] In 1171, poet Lou Yue [zh] described a place across the sea from Quanzhou, identified as Penghu, that had thousands of sandbars called "Pinghu" (flat lake) because of the "encircling shape of its inner coastline".

[8] In 1227, Wang Xiangzhi described Penghu as a group of 36 islands in an "outlying region" which took three days to reach by sailing from Jinjiang.

[9] In the Southern Min language, both Pinghu and Penghu are pronounced similarly, and scholars in Taiwan believe them to be the same place.

[14] Finds of fine red cord-marked pottery at Guoye, Huxi, indicate that Penghu was visited by Austronesians from southwestern Taiwan around 5,000 years ago, though not settled permanently.

A local official, Wang Dayou [zh] had houses built on Penghu and stationed troops there to prevent depredations by the Bisheye.

[17][18][16] Coins dating to the Xining (1068–1077) and Zhenghe (1111–1117) reign periods as well as many Song pottery and porcelain shards have been unearthed in Penghu.

A family [which owns some goats] brands their hair and cuts their horns as marks of identification, but does not gather them in during the day or night, so that they all forage for themselves.

Their workmen and merchants enjoy the profits of a flourishing trade.The territory is attached to Chin-chiang county [hsien] of Ch'üan-chou [prefecture].

When these restrictions were removed in the late 16th century, legal fishing communities, most of which hailed from Tong'an County,[22] were re-established on the islands.

[30] In 1624, the new governor of Fujian sent a fleet of 40–50 warships with 5,000 troops to Penghu and expelled the Dutch, who moved to Fort Zeelandia on Taiwan.

[31][32] For a period in the mid-17th century, Taiwan and the archipelago were ruled by the Kingdom of Tungning under the Zheng family, which was overthrown by the Qing dynasty in 1683 after the Battle of Penghu.

[33] The Penghu archipelago was captured by the French in March 1885, in the closing weeks of the Sino-French War, and evacuated four months later.

[34][non-primary source needed] Towards the end of the First Sino-Japanese War, having defeated the Qing in northern China, Japan sought to ensure that it obtained Penghu and Taiwan in the final settlement.

[35][non-primary source needed] Penghu County was then called the Hōko Prefecture by the Japanese government of Taiwan.

In World War II, Makō (Makung) was a major base for the Imperial Japanese Navy and the embarkation point for the invasion of the Philippines.

[36] Following the surrender of Japan on 2 September 1945, Supreme Commander of the Allied Powers Douglas MacArthur issued General Order No.

In the 1956 Japan v. Lai Chin Jung case, it was stated that Taiwan and the Penghu islands came to belong to the ROC on the date the Treaty of Taipei came into force.

[40] In the 1960 Sheng v. Rogers case, it was stated that, in the view of the U.S. State Department, no agreement has purported to transfer the sovereignty of Taiwan to the ROC, though it accepted the exercise of Chinese authority over Taiwan and recognized the Government of the Republic of China as the legal government of China at the time.

[41] Boat people fleeing Vietnam in the 1970s and 1980s who were rescued by Taiwan's ships in the South China Sea were sent to Penghu.

[42] On 25 May 2002, China Airlines Flight 611, a Boeing 747-200 aircraft flying from Taipei to Hong Kong, disintegrated and exploded over the Islands.

The stratigraphy of the island is dominated by two to four layers of basalt interbedded with sandstone and mudstone deposited in shallow marine conditions.

On 24 December 2010, the Taiwan-Penghu Undersea Cable Project of Taipower was approved by the Executive Yuan to connect the electrical grid in Taiwan Island to Penghu.

To reduce its groundwater use, in November 2015 the county secured a contract of building an additional desalination plant with 4,000 m3 capacity per day, construction of which is expected to be completed by May 2018.

[61] Since 1 January 2015, tourists from Mainland China can directly apply for the Exit & Entry Permit upon arrival in Penghu.

[63] As a lightly populated outlying island, Penghu lends itself to being used as a trans-shipment hub for drug smuggling into Taiwan from China and the Philippines.

Eight suspects were arrested in Cagayan, a small island in northern Philippines, but no Taiwanese nationals were charged in relation to the importation scheme.

[64] Ephedrine smuggling has increased in recent years as it has a similar structure to amphetamines and can be easily converted into methamphetamine.

According to a Focus Taiwan report, "(It) can then be sold for ten times the price, in this case that would be more than NT$1 billion (US$33.33 million).