Not necessarily a High Court, but the story of Ahab and Naboth seems to indicate the existence of a judicial system:
וַיַּעֲשׂוּ אַנְשֵׁי עִירוֹ הַזְּקֵנִים וְהַחֹרִים אֲשֶׁר הַיּשְׁבִים בְּעִירוֹ כַּאֲשֶׁר שָׁלְחָה אֲלֵיהֶם אִיזָבֶל כַּאֲשֶׁר כָּתוּב בַּסְּפָרִים אֲשֶׁר שָׁלְחָה אֲלֵיהֶם
קָרְאוּ צוֹם וְהֹשִׁיבוּ אֶת נָבוֹת בְּרֹאשׁ הָעָם
יָּבֹאוּ שְׁנֵי הָאֲנָשִׁים בְּנֵי בְלִיַּעַל וַיֵּשְׁבוּ נֶגְדּוֹ וַיְעִדֻהוּ אַנְשֵׁי הַבְּלִיַּעַל אֶת נָבוֹת נֶגֶד הָעָם לֵאמֹר בֵּרַךְ נָבוֹת אֱלֹהִים וָמֶלֶךְ וַיֹּצִאֻהוּ מִחוּץ לָעִיר וַיִּסְקְלֻהוּ בָאֲבָנִים וַיָּמֹת:
And the men of his city did, the elders and the officials that dwelled in his city, as Jezebel sent to them, as it was written in the letters that she had sent to them.
They proclaimed a fast, and they set Naboth at the head of the people.
And the two wicked men came and sat opposite him, and the wicked men testified against Naboth in front of the people saying, "Naboth cursed God and the king." And they took him out of the city and stoned him with stones, and he died.
The fact that Jezebel needed to go to such effort to orchestrate the scene and find "wicked men" to falsely testify against Naboth implies that there was some sort of court system in place that was not wholly controlled by the Crown.
