Flathead Lake is Extraordinary

Let's Keep It That Way

Flathead Lake is an Extraodinary Place

Let's Keep It That Way

Flathead Lake is an Extraodinary Place

Let's Keep It That Way

Help Stop the Spread of Invasive Mussels

Flathead Lake is one of the cleanest large lakes in the world. It is the crown jewel of the Crown of the Continent, and invasive mussels could ruin it. Let’s work together to protect and preserve this rare and priceless part of our collective heritage.
Flathead Lake is one of the cleanest large lakes in the world. It is the crown jewel of the Crown of the Continent, and invasive mussels could ruin it. Let’s work together to protect and preserve this rare and priceless part of our collective heritage.

Quick Reference

Check Station Information

Check Stations
(Locations and Hours)

Ravalli, MT
Hwy 93, next to the highway maintenance shop in Ravalli, MT
Opens: March 12th Closes: October 17th
Hours: Daylight
Mandatory Class I Inspection Station—full inspection and decontamination capability

Thompson Falls, MT
Opens: April 24th Closes: September 19th
Hours: Daylight
Mandatory Class I Inspection Station—full inspection and decontamination capability

Polson, MT
AIS inspections will be done in Polson Monday through Thursday during work hours. Anglers need to call ahead. The CSKT office is at 406 6th Avenue East, Polson (406) 883-2888 ext 7200 or 7237 or 675-2700 ex 7200 or 7237.
Courtesy Station, inspection and routing as needed.

Kalispell, MT
MFWP Region 1 Office, 490 N Meridian Rd, Kalispell
Opens: March 1st Closes: TBA
Hours March 1 to April 4: Monday through Friday, 8 a.m. to 5 p.m.;
Hours After April 4th: Monday through Friday, 8 a.m. to 5 p.m. and Saturdays, Sundays & Holidays 9:00 a.m. to 5:00p.m.
Courtesy Station, inspection, decontamination, and routing as needed.

Mack Days AIS Information

Mack Days AIS Update
Spring 2021
March 19 to May 16, 2021
Date of this Update: January 14, 2021

Because we are very concerned about AIS issues, Mack Days will require that all boats be inspected in 2021 before launching at any site on Flathead Lake and that proof of inspection be turned in with your first entries or before (you can email a copy of your proof of inspection to Cindy at cindy.benson@cskt.org). This is for the protection of the lake and everyone who cares about it.

Note that as in the past, we are conducting AIS inspections at Blue Bay for boats participating in Mack Days (except for boats coming from out of state or any boat crossing over the Continental Divide).


Thank you everyone and best of luck!

Help Stop the Spread of Invasive Mussels

Flathead Lake is one of the cleanest large lakes in the world. It is the crown jewel of the Crown of the Continent, and invasive mussels could ruin it. Let’s work together to protect and preserve this rare and priceless part of our collective heritage.
Flathead Lake is one of the cleanest large lakes in the world. It is the crown jewel of the Crown of the Continent, and invasive mussels could ruin it. Let’s work together to protect and preserve this rare and priceless part of our collective heritage.

Quick Reference

Check Station Information

Check Stations
(Locations and Hours)

Ravalli, MT
Hwy 93, next to the highway maintenance shop in Ravalli, MT
Opens: March 12th Closes: October 17th
Hours: Daylight
Mandatory Class I Inspection Station—full inspection and decontamination capability

Thompson Falls, MT
Opens: April 24th Closes: September 19th
Hours: Daylight
Mandatory Class I Inspection Station—full inspection and decontamination capability

Polson, MT
AIS inspections will be done in Polson Monday through Thursday during work hours. Anglers need to call ahead. The CSKT office is at 406 6th Avenue East, Polson (406) 883-2888 ext 7200 or 7237 or 675-2700 ex 7200 or 7237.
Courtesy Station, inspection and routing as needed.

Kalispell, MT
MFWP Region 1 Office, 490 N Meridian Rd, Kalispell
Opens: March 1st Closes: TBA
Hours March 1 to April 4: Monday through Friday, 8 a.m. to 5 p.m.;
Hours After April 4th: Monday through Friday, 8 a.m. to 5 p.m. and Saturdays, Sundays & Holidays 9:00 a.m. to 5:00p.m.
Courtesy Station, inspection, decontamination, and routing as needed.

Mack Days AIS Information

Mack Days AIS Update
Spring 2021
March 19 to May 16, 2021
Date of this Update: January 14, 2021

Because we are very concerned about AIS issues, Mack Days will require that all boats be inspected in 2021 before launching at any site on Flathead Lake and that proof of inspection be turned in with your first entries or before (you can email a copy of your proof of inspection to Cindy at cindy.benson@cskt.org). This is for the protection of the lake and everyone who cares about it.

Note that as in the past, we are conducting AIS inspections at Blue Bay for boats participating in Mack Days (except for boats coming from out of state or any boat crossing over the Continental Divide).

Thank you everyone and best of luck!

Help Stop the Spread of Invasive Mussels


Flathead Lake is one of the cleanest large lakes in the world. It is the crown jewel of the Crown of the Continent, and invasive mussels could ruin it. Let’s work together to protect and preserve this rare and priceless part of our collective heritage.

Quick Reference

Check Station Information

Check Stations
(Locations and Hours)

Ravalli, MT
Hwy 93, next to the highway maintenance shop in Ravalli, MT
Opens: March 12th Closes: October 17th
Hours: Daylight
Mandatory Class I Inspection Station—full inspection and decontamination capability

Thompson Falls, MT
Opens: April 24th Closes: September 19th
Hours: Daylight
Mandatory Class I Inspection Station—full inspection and decontamination capability

Polson, MT
AIS inspections will be done in Polson Monday through Thursday during work hours. Anglers need to call ahead. The CSKT office is at 406 6th Avenue East, Polson (406) 883-2888 ext 7200 or 7237 or 675-2700 ex 7200 or 7237.
Courtesy Station, inspection and routing as needed.

Kalispell, MT
MFWP Region 1 Office, 490 N Meridian Rd, Kalispell
Opens: March 1st Closes: TBA
Hours March 1 to April 4: Monday through Friday, 8 a.m. to 5 p.m.;
Hours After April 4th: Monday through Friday, 8 a.m. to 5 p.m. and Saturdays, Sundays & Holidays 9:00 a.m. to 5:00p.m.
Courtesy Station, inspection, decontamination, and routing as needed.

Mack Days AIS Information

Mack Days AIS Update
Spring 2021
March 19 to May 16, 2021
Date of this Update: January 14, 2021

Because we are very concerned about AIS issues, Mack Days will require that all boats be inspected in 2021 before launching at any site on Flathead Lake and that proof of inspection be turned in with your first entries or before (you can email a copy of your proof of inspection to Cindy at cindy.benson@cskt.org). This is for the protection of the lake and everyone who cares about it.

Note that as in the past, we are conducting AIS inspections at Blue Bay for boats participating in Mack Days (except for boats coming from out of state or any boat crossing over the Continental Divide).


Thank you everyone and best of luck!

Tiny, razor-sharp shells would coat and clog every hard surface of the lake – rocks, boats, docks & dams.

Tiny, razor-sharp shells would coat and clog every hard surface of the lake – rocks, boats, docks & dams.

Invasive mussels would ravage the lake environment.

They would devastate the lake fishery and cost taxpayers and property owners hundreds of millions of dollars. Protecting Flathead Lake from invasive mussels is up to all of us.

Clean Drain Dry is more than just a slogan. It's the key to keeping invasive mussels out of the lake. And stoping at check stations is not an option.
It's the law.

A vibrant fishery is a terrible thing to waste and 1.5 billion dollars is too much money to flush down the drain. We can't afford either.

Did you know that an adult female zebra mussel can release a million eggs a year and that the mussels that hatch from all those eggs will grow up to encrust any hard surface they can find?

  Watch the Public Service Announcement

Invasive mussels would ravage the lake environment.

They would devastate the lake fishery and cost taxpayers and property owners hundreds of millions of dollars. Protecting Flathead Lake from invasive mussels is up to all of us.

Clean Drain Dry is more than just a slogan. It's the key to keeping invasive mussels out of the lake. And stoping at check stations is not an option.
It's the law.

A vibrant fishery is a terrible thing to waste and 1.5 billion dollars is too much money to flush down the drain. We can't afford either.

Did you know that an adult female zebra mussel can release a million eggs a year and that the mussels that hatch from all those eggs will grow up to encrust any hard surface they can find?

  Watch the Public Service Announcement

Invasive mussels would ravage the lake environment.

They would devastate the lake fishery and cost taxpayers and property owners hundreds of millions of dollars. Protecting Flathead Lake from invasive mussels is up to all of us.

Clean Drain Dry is more than just a slogan. It's the key to keeping invasive mussels out of the lake. And stoping at check stations is not an option.
It's the law.

A vibrant fishery is a terrible thing to waste and 1.5 billion dollars is too much money to flush down the drain. We can't afford either.

Did you know that an adult female zebra mussel can release a million eggs a year and that the mussels that hatch from all those eggs will grow up to encrust any hard surface they can find?

  Watch the Public Service Announcement

Resources you need to prevent a mussel invasion.

Be a responsible boater. Don't let your legacy be the ruin of the crown jewel of the Crown of the Continent.

Resources you need to prevent a mussel invasion.

Be a responsible boater. Don't let your legacy be the ruin of the crown jewel of the Crown of the Continent.

Resources you need to prevent a mussel invasion.

Be a responsible boater. Don't let your legacy be the ruin of the crown jewel of the Crown of the Continent.