Each year the IMMG conducts field trips to geologic and mining points of interest. Led by university professors, local geologists, and knowledgeable enthusiasts, these wildly popular field trips are a unique opportunity to learn more about the history of our State and adjoining regions. And, they are great family fun!

Cost is $10 for IMMG members, $15 for non-members. Don’t forget members get one free field trip! Most field trips take up the good part of the day so always come prepared with plenty of food and water, and dress for all weather possibilities.

Below is our 2019 Field Trip schedule. If you have any questions, contact our Field Trip Coordinator Steve Cox at 853-1678 or cell  208-724-4679

2019 Field Trips

April 12 & 13th

Giants of Idaho Geology

A special two day trip with our own Dr. Terry Maley and Dr. Paul Link of Idaho State University. Friday April 12 will be a half day tour of sites around Boise; registration will be at the Museum at 11:30 AM with a departure soon after noon. Saturday April 13 we will register at the Museum early at 7:00 AM with a departure at 7:30 AM to travel to Bruneau Dunes State Park where we will join Terry and Paul (and special leader Shawn Willsey from CSI) for a day exploring sites toward Twin Falls. Both days with one registration fee. Pre-registration will be required because of traffic limitations. Call Steve Cox at 208-853-1678 and specify if you will be going on one day or both. On Saturday bring lunch and water and dress for the weather both days. Extensive hiking is not anticipated but good field footwear is always advisable.

NOTE: This trip is now filled. Sorry.

May 11th

Squaw Butte and the Mystery Boulder Field

Ander Sundell of the College of Idaho will revisit his very well received trip from last year to visit sedimentary features from Lake Idaho, the flood basalts of Squaw Butte and the never-explained boulder field on the approach to the Butte. Register at Winco on west State Street/Highway 55 at 7:30 AM with a departure at 8:00 AM. Dress for the weather, bring lunch and water, no pre-registration required. Vehicle note: the road up the Butte is OK for most ordinary vehicles unless it is wet; we may need to do a local carpool if necessary. No extended walking.


Here is a link to Ander’s handout:


June 15th

South Fork Boise River and Smith Prairie

IMMG Board member and retired geology professor Dr. Terry Panhorst will lead this wonderful tour of many of the most impressive features of local geology. This will include Danskin Mountain rhyolite, the Idaho batholith, the unusual geology of the Anderson Dam site, the picturesque South Fork of the Boise River, the largest metamorphic formation in our area and the “inverted stratigraphy” of lava flows down the South Fork. When we did this in 2015, Steve Cox led without the benefit of a professional geologist, so if you went then, you will want to go again with Terry’s expertise! We will also highlight some historical information about how Anderson Dam was constructed and life at the “Reclamation Village” where the dam workers lived.

We will register at the Museum at 7:30 AM with a departure at 8:00 AM. No vehicle restrictions and no long hiking will be required. No pre-registration needed. Dress for the weather, bring lunch and water. Expected return to Boise by 6:00 PM.

Link to articles related to this trip:

In the “S. Fork Tour and Anderson Dam” article, focus on the road log for Day 2, from Mile 113.6, including the Side Trip and Cow Creek Road to Mile 128.8.

Most of the Spencer Wood article is pertinent, although we won’t stop at the MP 103.3 and 107.7 locations.

The “Canyon Filling Basalts” article is generally pertinent.

Here is trip road log: Smith Prairie roadlog

July 20th

Gold Panning with the Idaho Gold Prospectors Association

Yes, we will again be guests of IGPA at their Lucky Lucy claim on Grimes Creek for the ever popular gold panning experience. This is a great trip for the kids as they learn the panning technique and have a chance to find the “colors” just like the old timers. The site is dry, no need for boots, but outdoor clothing and footwear are advised. IGPA is looking to enhance the day with extra demonstrations including how to smelt gold and possibly an historian to tell how prospecting and mining developed in the Boise Basin.

This year we will register at the Idaho City High School parking lot at 9:00 AM and groups will be guided to the claim periodically as participants accumulate; we would like everyone to get to Idaho City by 10:00 AM. A map of the High School is located below. No pre-registration required, bring lunch and water. You can leave when your poke is full.

Idaho City Map 2


August 17th

Finding Lake Idaho

Interns Brian Holm and James Duncan and preceptor Dr. Terry Panhorst will lead this trip that arose as part of development of the new Snake River Plain/Lake Idaho exhibit at the Museum, which is part of Brian’s degree fulfillment in geology at BSU. James has graduated from BSU in geology and wanted  to add to his field experience and has been assisting Brian. Together with IMMG Board member Dr. Panhorst, the two interns searched out evidence for Lake Idaho and have incorporated that information into the interactive touchscreen map display in the exhibit. The field trip will visit some of the more important sites that they uncovered in their research.

The first stop at the famous Gilbert Delta off of Mountain Cove Road does require a level walk of about 15 minutes each way: there is no other major walking required, but good field shoes are advisable because we will have a short walk to the Algal Reef. Another highlight is the Shoofly Oolite Interpretive Site; IMMG has not been to this spectacular location in many years.

We will register at the Museum at 7:30 AM with an 8:00 AM departure. Dress for the weather, bring lunch and water. No pre-registration is required. No vehicle restrictions, but some travel is on improved gravel roads. Return to Boise by 5:00 PM; the last stop near Grand View is optional for folks who need to be back in Boise earlier.

A trip log with site descriptions is located below.

Lake Idaho Field Trip Road Log

September 14th

Volcanics of the Western Snake River Plain

Dr. Brittany Brand, BSU will lead to several major features of Western Snake River Plain volcanic activity, including Initial Point, Sinker Butte, Guffey Butte and Guffey Table, Celebration Park and the Grouch Drain Maar. We will register at the Albertsons parking lot in Kuna (700 E. Avalon St.) at 8:00 AM with a departure at 8:30 AM.  A location map is located below. As usual, dress for the weather, bring lunch and water. No extended walking is anticipated. No pre-registration is required. The trip itinerary is also located below so you can print out your  own copy. Return to Boise by 4:00 PM.


 IMMG Field Trip Guide Sept 2019 Final

October 12, 2019

Lost Orbs of Idaho

IMMG geologist Coyote Short and her sidekick Janelle Wintersteen will lead us on a search for rare specimens of orbicular granite along the North and South Forks of the Payette River, including a site where an outstanding example was discovered last year. We have also been given special permission to visit the Ourada Ranch (at the head of Cartwright Road), where Coyote has discovered “graphic granite” in the past. A real highlight of the trip will be a stop at the Horseshoe Bend home of Tim and Dalles Kalac, rockhounds extraordinaire, who have an unbelievable collection of orbicular granite specimens from the areas we will be searching.

Register at the Museum at 7:30 AM with departure at 8:00 AM. Dress for the the weather (it could be cold and rainy), bring lunch and fluids.No pre-registration required. No long walks are anticipated, but good field footwear  will be important if you want to explore the rocks along the South Fork of the Payette River where the fantastic specimen was collected last year.Return to Boise by 5 PM.

A photo of “Norma’s Orb” from the South Fork can be found below. It is at least 8″ in long dimension and shows more concentric layers than usual.









Visit field trips from the past:

2012 Field Trips

2013 Field Trips

2014 Field Trips

2015 Field Trips

2018 Field Trips

Find other field trip information:

Field Trip Resources from the Web