There are many resources that can help you get a handle on your ancestors' surnames. One helpful resource are tools that can be used to map the frequency and distribution of a particular surname. These can tell you whether the name is specific to a particular region or is common throughout the country. If the name is relatively uncommon, these tools can help you narrow your search considerably. There are tools like this for many countries, including Poland. The site where you can map your Polish surnames is in Polish, but you should be able to figure out a lot just by context. Enter your surname in the box and click szukaj, which means "search".
There are two different types of maps one that gives the total number of the surname (Podział kompletny) and one that gives relative frequencies (Podział relatywny). To switch between the two types of maps click on these phrase to the right of a blue arrow.
With more common surnames the relative frequency map will be more useful because the absolute number will be highest in big cities, so you won't get the proper picture of where the name is most popular.
Also, pay close attention to the key for the map. The magnitude for the numbers will be quite different for a very common name like Nowak and a less common one like Szeszycki. The construction od...do... means "from...to...." and więcej niż means "more than". For Nowak the red is for "more than 2000".
But for Szeszycki, it is for "more than 12". This is a big difference.
The subdivision shown on the map is that of the county, or powiat. You can identify the county by moving the cursor over the map. For Szeszycki, you will find that the name is most common in the counties of Gniezno, Słupca and Krotoszyn, three counties, all in the province of Wielkopolska, or Greater Poland. This provides a place to start in your search.