These simple facts alone indicate that Sidon likely flows in a northward direction (along the east of Zarahemla), from its southern “head” or source near Manti. But there’s more:

Like the western NY countryside of young Joseph Smith, the main geography of the Book of Mormon has a general southern rise in elevation. For example, from the northern Jaredite land of Desolation one goes “up” to the land of Bountiful just to the south:

 31 And they came from there [Desolation] up into the south wilderness.  Thus the land on the northward was called Desolation, and the land on the southward was called Bountiful, it being the wilderness... (Alma 22:31 – emphasis added)

From the land of Zarahemla (south of Bountiful) one goes “up” to the land of Nephi (further south):

7 Nevertheless they departed out of the land of Zarahemla...

8 And thus they departed into the wilderness … to go up to the land of Nephi … (Alma 17:7-8 – emphasis added)

The “head of the river Sidon” situates in the southern highlands near the Nephite land of Manti. Sidon is also near the “line” of demarcation or “narrow strip of wilderness” which runs from a body of water called “the east sea” to “the west sea”. The east-west “line” separates the lower land of Zarahemla, from the more elevated land of Nephi (Alma 50:7-8) to the south:

27 … [the land of Nephi] bordering even to the sea, on the east and on the west, and which was divided from the land of Zarahemla by a narrow strip of wilderness, which ran from the sea east even to the sea west, …, through the borders of Manti, by the head of the river Sidon, running from the east towards the west—and thus were the Lamanites and the Nephites divided. (Alma 22:27)

11 And thus he [Chieftain Moroni] cut off all the strongholds of the Lamanites in the east wilderness, yea, and also on the west, fortifying the line between the Nephites and the Lamanites, between the land of Zarahemla and the land of Nephi, from the west sea, running by the head of the river Sidon—the Nephites possessing all the land northward, yea, even all the land which was northward... (Alma 50:11)

Fact: The southern Nephite – Lamanite dividing line, near the “head of Sidon” is at higher elevation than the land of Zarahemla (“down”). In other words, Manti and the neighboring head of the river Sidon were “up” with respect to Zarahemla. From its “southward” headwaters by Manti (south of Gideon), the river Sidon flowed along the east of Zarahemla (west of Gideon):

25  Neither durst they march down against the city of Zarahemla; neither durst they cross the head of Sidon, over to the city of Nephihah. (Alma 56:25 – emphasis added)

26  …the city of Nephihah, …on the east borders by the seashore. (Alma 51:26)

7  …Alma …in the city of Zarahemla, …went over upon the east of the river Sidon, into the valley of Gideon… (Alma 6:7)

1  …Alma was journeying from the land of Gideon southward, away to the land of Manti, behold, to his astonishment, he met with the sons of Mosiah journeying towards the land of Zarahemla. (Alma 17:1)

6  …the Lamanites will cross the river Sidon in the south wilderness, away up beyond the borders of the land of Manti.  And behold there shall ye meet them, on the east of the river Sidon…. (Alma 16:6 – emphasis added)

22 …in the wilderness, away by the head of the river Sidon, that they might come into the land of Manti... (Alma 43:22)

The river Sidon is of course never mentioned in the land of Nephi which situates southward from the river’s head and which resides at higher elevation than the land of Zarahemla. The “course of the land of Nephi” near “the line” running by the head of Sidon, was “above the land of Zarahemla”. (Alma 2:24; 50:8, 11)

More scriptures referring to Sidon on the east of Zarahemla: Alma 2:16, 26-27, 34; 6:7

Fact: The “river Sidon” is passable on foot near its southern head and downstream as it flows on the east of Zarahemla. (Alma 43:40; 2:26-27; 6:7)

Of the several referenced to the river Sidon in the book of Alma, only east and west sides of the river are mentioned. (Alma 2:34; 6:7; 8:3; 16:6; 43:27, 32, 35-36, 51-53, Alma 49:16) There is no indication that the river takes an extreme east or west excursion from its southern head, before flowing along the east of Zarahemla. The thing referred to as “…running from the east towards the west” in Alma 22:17 is a “narrow strip of wilderness, which ran from the sea east even to the sea west … by the head of the river Sidon …”

The Book of Mormon does not use the expression Sidon River, with “river” capitalized. The expression “river Sidon” = “נַחַל צִּידֹן” (in Hebrew) transliterates as “nahal Tsidon”. The Hebrew word “nahal = נַחַל” can mean either “river” or “brook”. The fact that Sidon is the only “river” explicitly named in the Book of Mormon’s American setting, likely has more to do with the fact that principal Nephite lands are geographically very localized - comparable in size to the land of Israel in the Old World. This means that Sidon does not have to be a particularly impressive river.

The rivers of Israel were not very impressive to outsiders like Naaman the Syrian. (2 Kings 5:12) To put things in scriptural perspective, Sidon should probably be compared more to the northward flowing “brook” or “river Kishon = נַחַל קִישׁוֹן” of northern Israel; which, though it is small, nevertheless swept away defeated dead as it flowed out to the great western sea (the inland Mediterranean). (Judges 5:21, 1 Kings 18:40 compare with Alma 3:3; 44:22) The biblical brook - river Kishon was famous to Israelites if to no one else.

The northward flowing “nahal Kishon”

Thus there is no scriptural justification for supposing that Nephite Sidon is a particularly mighty river comparable to the Nile or the Euphrates. There is no indication in scripture that Sidon was used for shipping on a scale comparable to one of the ancient sea-like rivers of the Old World, or on a scale comparable to the traffic of the port city Zidon (Sidon). We need only search out the meaning of the ancient name to understand why a creek or river would be called “Tsidon” = “Fishery” or “Catchery” or “Place of catching” (there is no explicit reference to fish in the name). No traffic of large merchant ships is necessarily implied. ^{[See Footnote from LDS Scripture Official Study Aids]}

It is possible, however, that a major Nephite port was built at the mouth of the river Sidon. Large ships may have harbored there and even trafficked along the river, near its mouth. We know that Sidon flowed out to sea (Alma 3:3; 44:22), but which sea?

The Book of Mormon indicates that it was in the “west sea” that “exceedingly large” Nephite vessels sailed. (Alma 63:5-8, Helaman 3:10) Similarly, the Mediterranean port city of Haifa situates at the mouth of the river Kishon. Haifa is the Israeli equivalent of Tyre or Sidon of old. Could their have been a port named "Tsidon" near the mouth of the American river?

Some may interpret Elder McConkie’s note that Sidon “runs north to sea”, to mean that Sidon maintains an unswerving northward course out to some sea; much like Colombia’s thousand mile Magdalena River (far too long to be Sidon). But, scripture doesn’t actually say that after flowing along the east of Zarahemla, the river continues northward to a sea.

It may be significant that Sidon is never mentioned in, or as flowing through, or by the lands of Bountiful and Desolation which are north of Zarahemla. We do know that “the land of Nephi and the land of Zarahemla were nearly surrounded by water”. (Alma 22:32) After flowing on the east of Zarahemla, the river Sidon may bend westward, constituting a watery northern border, as it flows out to the Book of Mormon “west sea”. In fact, Mormon 1:10 describes, "...the borders [plural] of Zarahemla, by the waters of Sidon."

So based on the Book of Mormon, in what general direction does Sidon likely flow as it runs along the east of Zarahemla?

Perhaps the Church committee working on the 2013 edition noticed that even though Sidon likely runs northward along the east of Zarahemla (from its southern head in the highlands near Manti), that the Book of Mormon does not explicitly say that Sidon maintains a direct northern course out to sea. In other words, Elder McConkie could have been quite correct in concluding that Sidon generally flows northward, but extrapolated, or over-generalized when he stated that Sidon “runs north to sea”.

The amended INDEX entry might therefore have properly read something like this:

SIDON, RIVER—the only river explicitly named in local Nephite territory, likely runs northward on the east of Zarahemla from its head in the southern highlands near Manti; and thereafter, by an unspecified way, flows out to a sea (see also River)

Alma 2:15 hill Amnihu is on east of S.; 2:34 Lamanites camp on west of S.; 4:4 many are baptized in waters of S.; 22:29 wilderness at S. 

But not wanting to add such detail, the committee may have opted instead to simply delete Elder McConkie’s over-generalized statement that Sidon “runs north to sea”.

The Nephite river “Jordan” (Likely the northward flowing Genesee) is implicitly named in scripture, in that a nearby city was named after it. (Mormon 5:3) Consider the meaning of the name “Yarden” or “Jordan”. Do you see why the name describes a river?

Footnote

Words likely related to Tsidon (i.e. Sidon son of Canaan, Genesis 10:15)

tsood (צוּד) = hunt (Brown-Driver-Briggs-Gesenius Hebrew – Aramaic Lexicon, 6679, pg. 844)

tsayid (צַיִד) = hunting game, provision, food (Brown-Driver-Briggs-Gesenius Hebrew – Aramaic Lexicon, 6718,  pp. 844, 845)

tsayad (צַיָד) = hunter (Brown-Driver-Briggs-Gesenius Hebrew – Aramaic Lexicon, 6719, pg. 844)

tsid (צִד) = take as one’s provision (Brown-Driver-Briggs-Gesenius Hebrew – Aramaic Lexicon, 6719, pg. 844)

Tsidon (צִידוֹן) = place of catching, possibly “fishery” by implication, but there is no explicit reference to fish in the name Sidon.

Of course, in the Americas, there are several rivers with names like “Fishing River” (LDS Doctrine and Covenants 105 chapter heading) or “Fish River”. This doesn't mean that any of these is “Sidon” (catching place) of the Book of Mormon. Its a fishy argument. Don't get caught by it!

Crossing Sidon (YouTube)