The geographical location of the Tvarditsa together with the sub-Balkan transport corridor - a railway and a highway Sofia - Karlovo - Bourgas, which passes through the municipality, favours the development of the transport and economic connections not only with the neighbouring municipalities, but also with the districts all over Bulgaria.
The name of the municipality's administrative centre - a symbol of pride, strength and bravery - is connected with the Gradishteto Fortress, situated 1.5 km south of the town. The name Tvarditsa comes from the old Bulgarian word tvardina, which means "fortress" or "fortification".
The relief is mostly mountainous and hilly. The territory of the Tvarditsa municipality is distributed into three geomorphologic areas - the Balkan, the Sredna Gora and the plain areas. The Balkan Area is shaped typically of the medium-height mountain relief - highly risen in their upper part rounded ridges with a southern exposure, furrowed by deeply sunken valleys, which pass into steep slopes and deep indentations in their lower parts. The Sredna Gora Area has a low-mountain hilly relief with a pronounced central ridge of the Sredna Gora Mountain. The Plain Area, consisting of the Tvarditsa Hollow (250 m above sea level) and the Shivachevo Hollow (200 m above sea level), is enclosed between the steep slopes of the Balkan on the north and the slanting slopes of the Sredna Gora Mountain to the south. The lowest point is situated in the valley of the Tounja River - 205 metres, and the highest point is the Choumerna Summit - 1 536 metres.