For over a century, the process of reducing the disproportions in the network of road connections between the territories of the country, which over 120 years ago was under three different partitions and developed at a different pace, has been constantly ongoing. As a result of the modernization works on existing roads or the marking out of new routes carried out in the 20th and 21st centuries, the spatial arrangements of large agglomerations as well as smaller towns and villages with urban traditions were modified many times. In the case of the latter, any interference could have significantly impacted the entire structure of the settlement. This text presents the original systematics and assessment of the impact of the expansion of the national road network on the historical urban layouts of small towns and the so-called cities degraded in eastern and southern Mazovia. The pro-posed systematics was based on the analysis of 20 cities, of which 4 examples were dis-cussed in more detail in the text, presenting various scales of direct interference in the historical structure of the city and the impact they had on it.