The Masaryk Circuit — known in Czech as Masarykův okruh and sometimes called the Masarykring — was one of several interwar European road circuits that linked public highways into a closed racing loop. The 1930 configuration at 29.194 km represented the original and longest form of the circuit. The start-finish line was situated in the suburb of Bosonohy, to the south-west of Brno's city centre. From there the route ran east past Kamenny, north past the Bohunice University Campus area in Kejbaly, and through the villages of Libusino, Kohoutovice, and Žebětín, extending out to Ostrovacice before looping back through a series of fast straights and kinks to return to Bosonohy. The character of the layout — long straights broken by sweeping bends on lightly adapted public roads — was typical of pre-war Grand Prix circuits across Central Europe.
Grand Prix racing at Brno in the 1930 configuration ran from 1930 to 1937, with the Czechoslovakian Grand Prix serving as the headline event. The races drew top-level competition from the dominant factory teams of the period and placed the circuit alongside other major European venues of the time. The full-length layout was used for this seven-year run before the series of events was suspended in 1938 and the circuit did not see further Grand Prix car racing until 1949.
After the Second World War, racing returned to Brno in a modified form. On 25 September 1949, the Czechoslovakian Grand Prix was held on a shorter 17.800 km variant of the old road circuit that ran clockwise rather than anti-clockwise. This version turned right at Veselka, bypassed Ostrovacice, and entered Žebětín from the south rather than the west. Although a crowd in excess of 400,000 people attended, this race proved to be the last Grand Prix for cars on any configuration of the old Brno road circuit. From 1950 the circuit was given over primarily to motorcycle racing.
The 1930 layout's 29.194 km length made it one of the longer interwar racing circuits in Europe. Its anti-clockwise direction of travel and the variety of road surfaces encountered across the route placed considerable demands on cars of the period. The circuit incorporated village roads and agricultural approaches, meaning surface conditions varied markedly from section to section. Long straights on the approach to Ostrovacice and on the return leg towards Bosonohy rewarded powerful cars, while the sections through Kohoutovice and Žebětín required more precise handling.
Subsequent modifications progressively shortened the usable circuit length. By 1964 it had been reduced to 13.941 km, bypassing Žebětín entirely and using newer road connections to reach Kohoutovice more directly. A further reduction to 10.921 km followed in 1975. All the public roads that formed the original 1930 circuit remain in existence as of 2025.
The 1930 Masaryk Circuit layout represents an important chapter in Central European motorsport history. Its seven-year run as a Grand Prix venue, the enormous crowds it attracted — culminating in the 400,000-plus attendance of the 1949 event — and its association with the interwar era of road racing gave Brno a motorsport identity that persisted long after the old layout was retired. The circuit's name and historical prestige informed the construction of the modern permanent Brno Circuit, which opened in 1987 within the geographical bounds once enclosed by the original road course, and which continues to host major motorcycle racing.