The Czech Republic rests on elevated tablelands, known as Bohemia, which extend west to the German border and east to Slovakia. Ranges include the Českomoravská Vysočina, Sudety, and Carpathian Mountains. They rise along the plateau’s edges, primarily to the north and east. The Bohemian Forest forms the southwest border with Germany. The central part of the plateau consists primarily of rolling hills, farmland, and fertile river beds.

The republic’s principal rivers include the Elbe, Vltava, Morava, and Oder.

The interior plateau areas of the republic experience a primarily continental climate, with warm summers and cold winters. The mountainous areas have harsher winters and receive heavy rainfall. The southern areas of the republic near the border with Austria have hot summers and milder winters.

The Czech Republic is heavily dependent on nuclear power. It operates eight reactors, and has plans for six more. Most of the remainder of the energy is produced by burning imported coal. Much of the coal burned is low quality with a high ash and sulphur content, producing high levels of air pollution. Partly as a result of this, the incidence of illnesses doubled in Prague between 1975 and 1990. Forests in the Czech Republic are among the most seriously affected by acid rain in all of Europe—about 57 per cent had been damaged by air pollution by the mid-1980s. Fertilizer applications are uncontrolled; in some areas of the country the nitrate content is so high that the water is considered unsafe for human consumption. Heavy rains across Eastern Europe that began in July 1997 caused major flooding in the eastern Czech Republic. The deluge killed at least 48 people and caused extensive environmental damage, inflicting massive costs on the country.

Within the Czech Republic about 3,500 plant species and 60,000 animal species are known, including invertebrates. There are three national parks and about 190 other reserves and specially protected sites and the government has ambitious plans to increase the extent of the system. Five biosphere reserves have been designated under the United Nations Educational, Scientific and Cultural Organization (UNESCO) Man and the Biosphere Program, and six sites have been declared under the Ramsar Convention on Wetlands. Overall, about 14 per cent of the country is protected. Acid rain, encroachment of agriculture, and tourist pressure are the main threats to protected land.