By Juliana Bunim, Main Street

Spam. It’s gross and messy and clogs your system.

No, not the infamous imitation meat, but the clutter stuffed in your online inbox screaming about online pharmacies, Nigerian diplomats and new software. But as it turns out, you could be combating significantly less spam that your Uncle Hank three states over. Why? Because spam distribution isn’t uniform, and according to the web security company Message Labs, certain states receive significantly more spam than others. MessageLabs scans three billion email connections daily and calculated the year-to-date spam rates for all 50 U.S. states.

Here are the 10 most spammed states:

1. Illinois

2. South Dakota

3. Oregon

4. New Hampshire

5. Wisconsin

6. North Carolina

7. Indiana

8. Texas

9. Pennsylvania

10. Alabama

It’s hard to explain why certain states are more vulnerable to spam. “How much spam an individual gets tends to be factored by how much email is distributed and how public or easy to find the person is,” says Matt Sergeant, senior anti-spam technologist for MessageLabs. Maybe it’s the financial center in Illinois or the farming community in South Dakota, but whatever the reason, residents are making their emails more widely available to the general public.

The first step to getting spammed is someone finding your email. “Basically spam is taking advantage of any way they can get an email into somebody’s inbox,” says Sergeant. Spam promoting Viagra (PFE), Cialis (LLY), penis enlargement, porn and fake online pharmacies is still prolific, but now spammers are capitalizing on the current political and economic climate as a way to peak your interest too.

“Two interesting things we’re seeing is a big rise in spam using news and current events like Obama and loan offers to attract you into opening the mail,” says Sergeant. But when you open it, there’s nothing about Obama at all, but a virus to link to a virus site. “It’s preying on people who are suffering from bad economies, and it’s tempting to get out debt and look for a quick fix for those problems,” says Sergeant.

Most people can look at the subject line of an email and know if it’s something they weren’t expecting to receive. But there are occasions when things look legitimate, but have questionable contents. “Don’t click links from people you don’t know, and certainly don’t click on anything that says it’s from your bank, Paypal or eBay (EBAY),” says Sergeant. “They generally won’t send you a link in an email, so open up your browser and access your information manually.”

To prevent spam landing in your inbox, you must assume you’re a target (even if you don’t live in a top 10 most spammed state). Make sure you have the most up to date antivirus software and a firewall. This requires you receive automatic updates so you’re always protected against the latest viruses and malware. You might think your free email service is filtering spam, but often sites like MSN (MSFT), Yahoo (YHOO) and Gmail (GOOG) aren’t capable of catching everything. If suspicious emails sneak through, make sure and label them as spam. And be wary of anything that comes with attachments or links, which can contain code designed to infect your computer.

And if you really want to up your chances of avoiding spam, you might want to consider moving to Montana. The “Treasure State” is the least spammed state in the nation.