What were the limitations on further US expansion at that war? why did they stop on the bank of the Rio Grande and in particular what stopped them from taking over Baja California?

  • 4
    There wasn't anything there. And still isn't. Sep 19, 2016 at 4:04
  • 3
    There wasn't anything in Alaska either
    – Ezra
    Sep 19, 2016 at 5:18
  • 6
    @user14394 Not so, I've just been there - there's tequila and fish tacos.
    – Dale M
    Sep 19, 2016 at 5:52
  • 2
    Since the US defeated the Mexican Army and occupied Mexico City, they weren't "stopped" from taking over Baja California; they just weren't interested in it. (The US had offered in 1845 to buy Nuevo México and Alta California from Mexico, which is an indication of a lack of interest in Baja California.) Sep 19, 2016 at 11:26
  • 2
    The US's interpretation of their border being the Rio Grande was the actual casus belli of the war in the first place. Going further south past that would have been tantamount to admitting they didn't really care about the treaty they were supposedly enforcing, and were just bullying a weaker neighbor.
    – T.E.D.
    Sep 19, 2016 at 14:21

2 Answers 2


"California" (at the time), consisted of three distinct regions:

1) A decidedly "Anglo" dominated area around the then-capital at Sonoma (modern northern California).

2) A "mixed" Anglo and Spanish-speaking area in the center (around Los Angeles),

3) A purely Spanish-speaking area in the south (the modern Baja California and Baja California Sur.

During the Mexican-American war, the "Americans" won decisively in the north, but fought a seesaw battle with the Mexicans around Los Angeles. When it came time to make peace, the U.S. Mexican boundary was drawn along a generally northwesterly "line" following the course of the Rio Grande and other rivers that made natural boundaries. The western end of the line started at the source of the Gila River (in modern Arizona), and extended westward to the Pacific Ocean, neatly dividing the "mixed" and Spanish speaking areas (2 and 3 above) to the north and south.

America "purchased" the land north of the border for $15 million, and later paid another $15 million for the Gadsden Purchase that "straightened" the southern borders of Arizona and New Mexico and allowed a railroad to be built through the territory.

  • IIRC, the reason for the Gadsen Purchase wasn't to straighten the border, but because that land contained the most convenient route for a southern transcontinental railroad. Otherwise, as with Baja, who would have wanted it?
    – jamesqf
    Apr 22, 2017 at 18:22

In every army there are men who will fight for their country, and, in the case at hand, there was a Captain named Manuel Pineda who fought for Mexico and its anti-slavery constitution of 1824. With a small force of Mexican soldiers and poorly armed routed a superior English/American (remember all thirteen original colonies were English and then called themselves Americans) force in several battles in Baja California. Later, after a tough fight and out of supplies and ammunition he and his men were captured,but the United States learning about the earlier Mexican victory agreed to the border at what is now San Ysidro, San Diego County.

If the U.S. had learned of the defeat of Manuel Pineda and his troops Baja California would be part of the United States, based on our history I have no doubt of that.

As stated by Professor Gutierrez who ever wins the war writes the historical accounts making sure they leave out hero's such as MANUEL PINEDA. However, history has a way of catching up and noting how and who was involved in the war, the incident, and the low down,selfish tactics used to overcome an enemy, and then take his land.

My best, Chuck Pineda; 8th United States Army veteran.

  • I don't believe this answers the question. Can you edit to make it clear why the US didn't occupy Baja?
    – MCW
    Apr 22, 2017 at 11:18
  • 1
    @MarkC.Wallace I think the answer means to say that the US was signing the peace treaty before they had heard that the man responsible for turning the tide of the war was defeated, so they took what they could get instead of fighting a while longer to secure a decisive victory. But without sources I'm hesitant to edit the answer.
    – SPavel
    Apr 22, 2017 at 20:46
  • Sources would also improve this answer.
    – MCW
    Apr 22, 2017 at 20:47
  • @Spavel - You are probably right, but I had to read it multiple times and I'm still not entirely sure.
    – MCW
    Apr 22, 2017 at 20:48

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