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Istria 100 by UTMB Umag, Istria County, Croatia

Name: Istria 100 by UTMB
Start: 2027-04-02
End: 2027-04-04

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Istria 100 by UTMB

Course maps

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HelloDrifter does not warrant the accuracy of this course data; it is provided for informational use only. Verify the course against the event organizer's published materials before relying on it for navigation or safety-critical activities.

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Istria 21K
Istria 42K
Istria 69K
Istria 110K
Istria 168K

Foot race | 2 Apr 2027

104.0 mi

Distance

Elevation gain

4,501 ft

Elevation high

1,424 ft

Elevation avg

Mixed

Elevation loss

0 ft

Elevation low

24%

Climb factor

What is climb factor?

The climb factor for a course is the percentage of your energy used in hill-climbing compared to the energy expended running the flats.

This course has a climb factor of 24% over 104.0 mi, which means that the energy expenditure for the run is equivalent to running a flat 128.5 mi.

Climb factor is provided courtesy of Ben Crowell, who both authored climb factor's scientific paper and wrote the open source software for it. You can read more about it here .

Course last updated 10 Oct 2026

All values approximate

Distance & elevation data

The distance or elevation data not precisely what you expect for this route?

Data from a GPS device can be rough, especially in areas where the terrain (trees, canyons) interfere with GPS signals. And routes drawn on our maps are reliant on people marking trails from satellite images -- the details of which can be hidden by trees.

Elevation can be tricky too. Elevation data is stored on spaced topographical lines, and determining the elevation of a point requires computers to estimate based on how close the point is to the topographical line.

We mitigate this by calculating distance in 3-D (think Pythagorean theorem) and using mathematical techiniques to smooth the elevation data. We come close, but no one can be perfect with imperfect data, even in 2026.

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Istria 100 by UTMB - Istria 168K course map

Stats summary

Race distance	Distance	Ele gain	Ele loss	Ele avg	Paved	Gravel	Dirt	Narrow
Istria 21K	13.4 mi	591 ft	1,486 ft	394 ft	22%	69%	9%	21%
Istria 42K	26.3 mi	3,428 ft	3,930 ft	531 ft	25%	57%	18%	20%
Istria 69K	43.0 mi	7,864 ft	8,104 ft	535 ft	23%	63%	14%	16%
Istria 110K	69.0 mi	13,734 ft	13,973 ft	1,037 ft	23%	56%	21%	19%
Istria 168K	104.0 mi	22,300 ft	23,261 ft	1,424 ft	21%	59%	20%	27%