Question about techum shabbat

I understand that it is 2000 cubits but I read this " This 2000 amos boundary only starts at the edge of the city. This means that if the city is 10 kilometers in size, then the person can travel a length of 12 kilometers without violating Shabbos "

So does that mean if I live in a big city and my schul is slightly over a mile aways I can still walk to it by virtue of being in a city??