Theme: Float Trip - the four rivers defined by the circles do not indicate country's borders but they do indicate the border's of the entry that they are part of.
58. It may straddle neighboring countries ... and, in a different way, what each of four sets of puzzle circles graphically depicts : BORDER RIVER
Argyle here. C.C. there. Cool how the longest river is in the longest answer. Four strong column words.
Across:
1. Adjust for daylight saving time, e.g. : RESET
6. Veggies in a sack : SPUDS
11. Sphere in the night skies : ORB
14. The first Mrs. Trump : IVANA
15. Plains dwelling : TEPEE
16. "Watch it!" : "HEY!"
19. Minn. summer hours : CDT. (Central Daylight Time)
20. Bambi's aunt : ENA
21. Heart : CORE
22. __ one's nose into: meddle : POKE
28. Ballroom moves : DIPS
29. Bit of buckshot : PELLET
30. Captain Picard's counselor : TROI. Star Trek: The Next Generation
33. Eat : DINE
34. Imprecise ordinal : NTH
41. __ Friday's: restaurant chain : TGI
42. Fuel from a bog : PEAT
43. Pretty pitcher : EWER
44. Youngster : MOPPET. Not much in common use these days.
46. Mosque official : IMAM
53. __ Major: Big Dipper : URSA
54. Double-reed woodwind : OBOE
55. Here, in Juárez : ACÁ
57. Bloke's bathroom : LOO
62. Target of fall shots : FLU. Big push to get your shots already.
63. Snoring cause, often : APNEA
64. Disbursed : SPENT
65. Labor Day mo. : SEP. (September)
66. Foppish neckwear : ASCOT
67. Lightens up : EASES
Down:
1. Word from the bailiff : RISE. Preceded by ALL.
2. Happening : EVENT
3. Comedian Silverman : SARAH
4. Ltr. holder : ENV. (envelope)
5. Meditative Chinese discipline : TAI CHI
6. Outboard motor areas : STERNS. The back of the boat.
7. "Moby Dick" ship co-owner : PELEG. Captains Peleg and Bildad were retired Nantucket whaling captains who co-owned the Pequod.
8. Longtime newswire org. : UPI. (United Press International)
9. Bear's home : DEN
10. "Catch my drift?" : "SEE?"
11. "You've got to be kidding!" : "OH, COME NOW!"
12. Salvation Army symbol : RED KETTLE
13. Memory units : BYTEs
18. Clever move : COUP
22. Friend : PAL
24. Prepare for publishing : EDIT
25. Grand-scale tale : EPIC
26. Gambling town near Carson City : RENO
27. Small valley : GLEN
30. Explosive initials : TNT
31. Complicated procedure : RIGMAROLE
32. Course served in a small crock : ONION SOUP
33. URL part : DOT
35. The Beatles' "And I Love __" : HER
37. Omar of "House" : EPPS
38. Bygone depilatory : NEET
39. Set of numbers next to a contract signature : DATE
40. Round before the final : SEMI,. Play-offs.
45. FedExCup org. : PGA. (Professional Golfers' Association)
46. "That wore me out!" : "I'M BEAT!"
47. "Wuthering Heights" setting : MOOR
48. Not at all eager : AVERSE
49. Large bays : GULFS
50. Bull rider's venue : RODEO
51. Roof edges : EAVES
52. Public spectacle : SCENE
56. Partner of sciences : ARTS. Arts and Sciences is often said of colleges and universities.
58. Cry from a lamb : [BAA!]
59. Black __: spy doings : OPS. (operations)
60. GOP org. : RNC. (Republican National Committee)
61. Hoppy brew, for short : IPA. (India pale ale)
Argyle