Is it possible to connect LAN between 2 systems which are located in different areas and connect with same ISP ?
Yes, most ISP's provide Layer3 connections between different branch locations. The provider then, dont have to use a VPN, cause they own the network in between your locations. For you, this is a transparent Layer3 connection. You dont have to setup a VPN or anyhing. But those connections are usually more expensive.
1. Buy cheap internet line -> Get expensive equipment -> do VPN yourself 2. Buy expensive layer3 service -> Equipment provided by ISP -> dont have to do anything
If you actually want to bridge your LANs across distance, look for something like MPLS or "metro ethernet" from the ISP. Most people in networking however prefer to route at distance rather than make "wide-area LANs".
If you want to connect your IP networks, you could just use public addresses, then you can just route as normal. IPv6 might be specially helpful here.
Lastly of course you can use a VPN of your own, your ISPs, or a third-party service.