Obrenovac is located almost in the centre of the northern moderately warm zone, with a climate milder than the typical Panonian and continental weather. Average annual temperature in this area is about 11o Centigrade, in summer about 22o and in winter 1o below zero. The extreme temperature values range from -28o to 40o. Within a year 640 litres of water per square metre drench the soil of Obrenovac, on average again, for in the years of drought there hardly fall 440 litres whereas in the years of heavy rains up to 940 litres per square metre pour down. The yearly pattern of rainfall, with increases during spring and at the turn of summer into autumn is very favourable for agriculture.
Agriculture has always been the foundation of the economy in the Obrenovac area due to the fertility of the soil in the broad river valleys and advantages of the climate and altitude. Of course, there are more than 15 thousand acres of cultivated land. Embankments and a thick network of drainage canals turned what used to be large swamps between the rivers and along the Sava into tillable fields. At last, a little over 1 thousand acres of land is covered with woods.
Layers that rivers had settled for millennia formed rich strata of the Panonian thickets, from which "rose" brick and tile industry. That is why, more than a hundred years ago, Obrenovac was called "a town that builds other towns". The industry still exists.
Except in the ancient ages, Obrenovac has not really been a mining region. But it is situated in the close neighbourhood of the vast Kolubara coal basin. For decades, Obrenovac has been the most significant destination for the enormous quantities of the coal dug out from the basin. And it is this adjacency to the coal sites, to the river Sava and its water profusion as well as to Belgrade as the centre of consumption, that "selected" Obrenovac as the seat for two largest thermal power plants in Serbia and the Balkans. They were constructed during the 1970s and 1980s respectively.
The decades long "relocations" of the earth have had a lasting impact on these parts - coal depots for the boilers of the power plants and ash wastelands stretch over five hundred acres of land. Hard to restrict, they often seem much larger since sudden winds may "remind" a lot remoter districts of the existence of the plants. Protective ponds are on top of them as if to imply the influence these industrial giants have on the underground streams. The ponds partly make up for the loss of the former swamps, both to the landscape and the local biosphere.
Finally, the townsmen, who, rooted deeply in this land brought to life by its waters, in mutual interactions, in ancient and more recent times alike, have impacted distinct marks into the
tissue of the town we are talking about. The population amounts to 71 thousand in the territory of the entire Municipality, while a little over one-third of that number live in the town itself.
Beside the town area, there are 27 settlements in the Municipality. Villages of Baric, Mislodjin, Jasenak, Drazevac, Konatice, Baljevac and Mala Mostanica are situated on the right-hand bank of the Kolubara river and within the basin of its tributaries. In the Tamnava basin there are villages of Belo Polje, Zvecka, Veliko Polje, Stubline, Poljane, Piroman, Brovic, Ljubinic, Dren, Orasac, Trstenica, Vukicevica and Grabovac. Lined up along the Sava are Skela, Usce, Urovci, Ratari, Krtinska, Rvati and Zabrezje.
Quite contrary to what may be expected due to the character of the terrain, the Obrenovac villages are not all typical for flatlands. Variations in the relief and cultural patterns that the population brought, sculpted different sorts of villages. Mountainous villages are dispersed along the upper and middle courses of the Tamnava and over the right-hand bank of the Kolubara, with houses grouped into hamlets, growing in time and melting into larger units. The Tamnava-type villages are rather spacious, as they are situated on the Tamnava plateau, so the houses stand wide apart from one another, built in the flat terraces and not in the river valley. Field-type villages are located right beside the river Sava, in the low flatland. Their houses with small backyards may be lined along the main village roads as in Zabrezje, Krtinska, Zvecka, or scattered without any order as in Skela, or concentrated to a certain degree around a core from which they spread radially toward peripheral ends as in Usce, Belo Polje and Rvati. There are also road villages, built along the main roads, where the centre is usually the village school, a bus stop, an inn, the administrative office…
The traces of the material culture, remnants of roads and communes etc. suggest the existence of human settlements in this end of Posavina from the very distant past. The marks lead us all the way back to the Neolithic period and show us routs of the solid roads of the ancient Romans. In different epochs, the Obrenovac parts used to play big roles in the huge history theatre. Various ethnic groups replaced one another, particularly from the Illyrian period on. After the Illyrian and Romanian peoples, there came Slavic population. Another change of the ethnic structure took place with the Turkish conquest of the region. Frequent wars between Austria and Turkey influenced further ethnic modifications and sometimes brought about complete dying out of certain settlements. In the first census organised by the Austrian authorities in 1717, only 11 subjects were registered in Palez, whereas some surrounding villages were totally desolate!
Upon liberation of Serbia, the Turkish families abandoned the area for good. At the same time here settled folk from numerous other regions - from Montenegro, Herzegovina, Bosnia, Raska, East Serbia and Dalmatia, as well as from Srem and other neighbouring parts, Macva, Podrinje, Kolubara Basin … The population of Obrenovac had a more significant increase only in the 1970s, which was a result of the enthusiastic industrial development. There hardly were 6 thousand inhabitants during the 1960s. Nowadays their number is five times bigger, partly due to the inflow of immigrants from other regions, and partly due to reduced outflow of residents as well as birth rate. Most of the people in the Municipality are Serbs (over 67 thousands) and there are Roma (about 1 thousand) while other ethnic groups are present in insignificant numbers.