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

AIS Check Stations
(Locations and Hours)

Ravalli, MT
83084 US-93, Ravalli, MT 59863
Open March 12th to October 23rd from 7:00 a.m. to 7:00 p.m.
From May 15th to September 18th the station is open 24/7
Contact: Ravalli office's numbers:
406-883-2888 ext. 5465
406-675-2700 ext. 5465
Mandatory Class I Inspection Station—full inspection and decontamination capability.

Thompson Falls, MT
Located next to Thompson Falls Rural Fire Station on HWY 200
Open April 23rd to September 18th from 7:00 a.m. to 8:00 p.m.


Polson, MT
406 6th Ave E Polson, MT.
Hours: M-Th by appointment.
Main office numbers:
406-883-2888 ext.7200, 7261
406-675-2700 ext 7200 or 7261

Kalispell, MT
MFWP Region 1 Office, 490 N Meridian Rd, Kalispell
Opens: February 28th Closes: TBA
Hours February 28 to April 24: Monday through Friday, 8 a.m. to 5 p.m.;
Hours beginning April 25th: Saturday through Sunday & Holidays, 9 a.m. to 5 p.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!

Contact Us

Contact Us

If you need to contact an inspector, want to schedule an inspection in Polson, or have questions about the Tribes' efforts to control aquatic invasive species, you can call us or leave a voice mail at (406) 675-5465.

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

AIS Check Stations
(Locations and Hours)

Ravalli, MT
83084 US-93, Ravalli, MT 59863
Open March 12th to October 23rd from 7:00 a.m. to 7:00 p.m.
From May 15th to September 18th the station is open 24/7
Contact: Ravalli office's numbers:
406-883-2888 ext. 5465
406-675-2700 ext. 5465
Mandatory Class I Inspection Station—full inspection and decontamination capability.

Thompson Falls, MT
Located next to Thompson Falls Rural Fire Station on HWY 200
Open April 23rd to September 18th from 7:00 a.m. to 8:00 p.m.


Polson, MT
406 6th Ave E Polson, MT.
Hours: M-Th by appointment.
Main office numbers:
406-883-2888 ext.7200, 7261
406-675-2700 ext 7200 or 7261

Kalispell, MT
MFWP Region 1 Office, 490 N Meridian Rd, Kalispell
Opens: February 28th Closes: TBA
Hours February 28 to April 24: Monday through Friday, 8 a.m. to 5 p.m.;
Hours beginning April 25th: Saturday through Sunday & Holidays, 9 a.m. to 5 p.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!

Contact Us

Contact Us

If you need to contact an inspector, want to schedule an inspection in Polson, or have questions about the Tribes' efforts to control aquatic invasive species, you can call us or leave a voice mail at (406) 675-5465.

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

AIS Check Stations
(Locations and Hours)


Ravalli, MT

83084 US-93, Ravalli, MT 59863
Open March 12th to October 23rd from 7:00 a.m. to 7:00 p.m.
From May 15th to September 18th the station is open 24/7
Contact: Ravalli office's numbers:
406-883-2888 ext. 5465
406-675-2700 ext. 5465
Mandatory Class I Inspection Station—full inspection and decontamination capability.

Thompson Falls, MT
Located next to Thompson Falls Rural Fire Station on HWY 200
Open April 23rd to September 18th from 7:00 a.m. to 8:00 p.m.


Polson, MT
406 6th Ave E Polson, MT.
Hours: M-Th by appointment.
Main office numbers:
406-883-2888 ext.7200, 7261
406-675-2700 ext 7200 or 7261

Kalispell, MT
MFWP Region 1 Office, 490 N Meridian Rd, Kalispell
Opens: February 28th Closes: TBA
Hours February 28 to April 24: Monday through Friday, 8 a.m. to 5 p.m.;
Hours beginning April 25th: Saturday through Sunday & Holidays, 9 a.m. to 5 p.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!

Contact Us

Contact Us

If you need to contact an inspector, want to schedule an inspection in Polson, or have questions about the Tribes' efforts to control aquatic invasive species, you can call us or leave a voice mail at (406) 675-5465.

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.