The United States has confirmed its participation in GREEN×EXPO 2027 and became the first G7 country to sign an official participation contract. The contract was signed as of January 14, 2026, according to the GREEN×EXPO Association’s announcement on February 6, 2026. Thomas E. Austin, Commissioner General for the United States Pavilion and Architect of the Capitol (AOC), signed it with Association Secretary General Masato Kawamura, and Government Commissioner Ambassador Kazuhiko Koshikawa countersigned. Information is current as of September 2026.
Basics
Figures are from the Ministry of Foreign Affairs of Japan’s basic data page.
| Item | Detail |
|---|---|
| Area | 9,833,517 sq km (50 states; about 26 times the size of Japan) |
| Population | About 342.35 million (U.S. Census Bureau estimate, February 2026) |
| Capital | Washington, D.C. |
| Language | Mainly English (no legal designation, though a March 2025 executive order, No. 14224, made English the national language) |
| Religion | Freedom of religion guaranteed by the constitution; predominantly Christian |
| Government | Presidential system, federal republic (50 states and other territories) |
| Head of state | President Donald J. Trump (took office January 20, 2025) |
| Japanese nationals residing in the U.S. | 416,380 (as of October 2025) |
| U.S. nationals residing in Japan | 69,787 (as of end of December 2025) |
| U.S. Ambassador to Japan | George Glass (as of June 2026) |
Japan and the United States share fundamental values and strategic interests, and their alliance is centered on the Japan-U.S. Security Treaty. Recent high-level visits include Japan’s Prime Minister and Foreign Minister traveling to the U.S. in March 2026, and the U.S. President and Secretary of State visiting Japan in October 2025.
Official exhibit information
The venue for GREEN×EXPO 2027, the horticultural exposition in Yokohama, is the former site of the Kami-Seya Communication Station. According to the Association’s press release, the U.S. Navy operated the station from the 1950s until the late 1990s, and it was then returned to the Japanese government. Given that history, the Association describes U.S. participation as reaffirming “the enduring friendship between the peoples of Japan and the United States” for visitors.
The exhibit is led by the United States Botanic Garden (USBG), which operates under the Architect of the Capitol (AOC), with full cooperation from the American Public Gardens Association (APGA). APGA is a nonprofit that has promoted the conservation, education, and appreciation of plants through public gardens for more than 80 years. Mary Glass, wife of U.S. Ambassador to Japan George Glass, was appointed as the representative for the U.S. exhibit. She is described as drawing on her expertise in American horticulture and landscape design, and her respect for Japan’s long relationship with nature, to introduce American horticulture, innovation, and cooperation.
Preparations began on January 15, 2026, when USBG Executive Director Dr. Susan Pell visited the venue site together with the exhibit design team. The U.S. exhibit’s theme is “The Pursuit of Happiness.” According to the announcement, the exhibit aims to connect visitors across cultures and generations through the diversity of American plants and public gardens. The Association says this theme echoes the overall GREEN×EXPO 2027 theme, “Scenery of Happy Tomorrow.” As of September 2026, specific pavilion design and exhibit content have not been announced.
A cultural primer
According to the official site of the United States Botanic Garden (USBG), which leads the U.S. exhibit, the garden was established by the U.S. Congress in 1820 and is the oldest continuously operating public garden in the United States. Its mission is to enrich society by displaying, studying, and conserving plants, and it welcomes more than a million visitors a year.
The garden is organized into three main areas: the Conservatory, which recreates environments from desert to tropical; the outdoor National Garden, centered on plants of the mid-Atlantic region and featuring a rose garden; and Bartholdi Park and Fountain along Independence Avenue. Bartholdi Park is presented as a place to see varied approaches to sustainable home gardening. The garden highlights roses, orchids, and the large-flowered Amorphophallus titanum, known as the corpse flower. USBG’s strategic plan for 2023–2027 emphasizes expanding a more diverse, conservation-relevant living collection, along with urban agriculture and international partnerships.
How this garden culture will be reflected at the Yokohama venue has not been announced as of September 2026.
Our take
The exposition will be held on the site of a former U.S. military facility, so we think it is a notable sign of Japan-U.S. friendship that the United States was the first G7 country to sign. It is also unusual that a public garden established by Congress, not a national tourism body, is leading the exhibit, so the presentation may focus more on horticulture and garden culture than on politics. The pavilion design and exhibit content have not been announced yet, and we will update this article when more details come out.
A regional list of participating countries is on the feature page “Participating countries.” For the dates, getting to the venue, tickets, and places to stay, see our GREEN×EXPO 2027 page.