Who has toughest travel schedule? Easiest?

Mariners will fly more miles than any other team in 2016

Who has toughest travel schedule? Easiest?

The amount of travel required during a Major League season can be an underrated part of the grind all players endure over six months and 162 games.

No, big leaguers aren't cramming into middle seats on commercial flights. Their transportation is relatively luxurious. Still, it's a lot of miles and a lot of hours spent en route.

Obviously, not all travel is equal throughout a league that is spread across the United States -- and into Canada -- so some clubs face a more daunting schedule than others. Here is a closer look at how that is shaping up in 2016:

• Interactive team schedule map

1. Long slog for Seattle yet again
The Mariners are slated to lead the Majors in miles traveled, at 47,704, and that's about as surprising as Clayton Kershaw notching a quality start. Seattle, of course, is a bit isolated up there in the Pacific Northwest, with the nearest division rival (Oakland) nearly 700 miles away. Over the previous seven seasons, the Mariners traversed the most miles in the league five times, and they are the only club to crack the 50,000-mile barrier (2011, '13, '14). Their 53,415 miles in '11, when they went 67-95, were the most in the Majors that year by a margin of 6,635

The Mariners will travel an MLB-high 47,704 miles during the 2016 season.

2. Mariners' frequent-flier accounts dwarf Reds'
Over that seven-year period, the Mariners traveled a total of 334,928 miles -- or 161,768 more than the Reds. That difference is roughly equivalent to circling Earth's equator 6 1/2 times. And coincidence or not, Seattle owns MLB's longest postseason drought, having last qualified in 2001.

3. Cubs check in with easiest travel slate
The Cubs already are a hot World Series pick this season, but they have something else going for them besides a talented roster. The club also will travel the fewest miles in the league, at 24,271, about 400 fewer than the Nationals. Meanwhile, the rival Cardinals and Pirates both will rack up more than 26,000 miles in 2016.

The Cubs will travel barely half as many miles as the Mariners over the course of the 2016 season.

4. Central teams obviously catch a break on travel
The Cubs' situation is not an outlier. When it comes to big league travel, it's good to be in the central region. Eight of the nine teams with the least miles in 2016 inhabit either the American League Central or National League Central, with the Nats the only exception.

From 2009-15, the Reds had the lowest average distance (24,737), followed by the Cardinals, Brewers, White Sox and Cubs. Last season, Cincinnati (20,612), St. Louis (20,875) and the Cubs (20,953) enjoyed the three lowest totals over that period, with the latter two winning 100 and 97 games, respectively.

5. West is not the best when it comes to travel
On the other hand, travel is most difficult for clubs closer to the West Coast. Including the Mariners, the eight teams with the most miles to go in 2016 all belong to the AL West or NL West. With the Angels (44,945), A's (42,119) and Rangers (41,128) following Seattle, that division holds each of the top four spots. Over the previous seven seasons, the top five most-traveled teams all hailed from the Pacific Time Zone, as the A's, Angels, Giants and Dodgers trailed the Mariners.

6. Astros, Rockies have it easier than Mariners, Dodgers
The second- and third-largest intradivision gaps occur in the AL West and the NL West, respectively. The Mariners will cover 9,151 more miles than the Astros, and the Dodgers will traverse 7,007 more miles than the Rockies.

7. Colorado's mileage total Rox compared to division rivals
NL West clubs not only have to contend with visiting Coors Field several times per season but also with tougher travel schedules than their mile-high counterparts. In 2016, the Rockies will cover the fewest miles of any team in the division for the eighth straight year, and their average over that span is more than 5,000 miles less than the closest rival (Arizona).

8. Marlins must contend with more travel to be beast of the NL East
If the Marlins are going to upset the Mets and Nationals in the NL East this season, they are going to have to overcome their schedule to do so. Because of its extreme southern location, Miami will travel nearly 6,000 more miles than any other team in its division and more than 8,000 more than New York. The Marlins' 10,562 additional miles over the Nats is easily the largest gap within any division. That has been a persistent issue for Miami, which has averaged nearly 9,000 more miles than Washington per season since 2009.

9. Rays have uphill swim when it comes to AL East mileage
The Rays find themselves in a similar, if less extreme, predicament as their fellow Florida club. Although Boston is only a tiny bit behind in 2016, Tampa Bay is set to top the AL East in distance covered for the seventh time in eight years, traveling 4,594 more miles than Baltimore. The difference between the Rays and O's has been as large as 12,141, back in '11.

10. Houston, we have a travel advantage on AL West rivals
When the Astros moved from the NL Central to the AL West for the 2013 campaign, their average number of miles per season climbed, thanks to all of those West Coast trips for divisional games. But relative to its division foes, Houston made out well. As mentioned, the 'Stros have the lightest schedule in '16, for the third time in four years since the switch. In three of the previous four seasons, they led their old division in distance, including by nearly 6,000 miles in that final year.

Andrew Simon is a reporter for MLB.com. Follow him on Twitter @AndrewSimonMLB. This story was not subject to the approval of Major League Baseball or its clubs.